136: Poison Centers and Poison Epidemiology

In 1950, the American Academy of Pediatrics created a Committee on Accident Prevention to explore methods to reduce injuries in young children. A subsequent survey by that committee demonstrated that injuries resulting from unintentional poisoning were a significant cause of childhood morbidity. Simultaneously came the realizations that a source of reliable information on the active ingredients of common household xenobiotics was lacking and that there were few accepted methods for treating poisoned patients. In response to this void, the first poison center was created in Chicago in 1953.¹⁰² Although initially designed to provide information to health care professionals, both the popularity and the success of this center stimulated a poison center movement, which rapidly spread across the country. The myriad of new poison centers not only offered product content information to health care professionals, but also began to offer first aid and prevention information to members of the community.

In the 60 years that have since passed, countless achievements have been realized by a relatively small group of remarkably altruistic individuals. Throughout this time, poison services have remained free to the public, highlighting their essential role in the American public health system. Many of the legislative and educational accomplishments, which are chronicled in Chap. 1, have directly reduced the incidence and severity of poisoning in children.^98,110,116 Concurrently, the number, configuration, and specific role of poison centers have shifted in response to public and professional needs.^50,125

Modern regional poison centers are staffed by highly trained and certified health professionals who are assisted by extensive information systems. Support is provided by 24 hour access to board certified medical toxicologists and consultants from diverse medical disciplines, the natural sciences, and industry. The role of the current American poison center can be best summarized as follows:

• Maintaining and interpreting a database of xenobiotics

• Reducing health care costs related to poisoning through:

  • Providing information and advice to the public to prevent unnecessary hospitalizations following exposure

  • Providing information and advice to health professionals to improve the diagnosis and care of patients who present to health care

• Collecting epidemiologic data on the incidence and severity of poisoning

• Integrating epidemiologic data as part of the public health surveillance system

• Educating health care professionals on the diagnosis and treatment of poisoning

• Contributing to the science of toxicology

In the past, poison centers were evaluated based on number of incoming calls and measures of community awareness. Current emphasis should be placed on evaluating health outcomes such as admissions to the intensive care unit, length of stay in hospitals, and total health care expenditures. One crucial test of the utility of modern poison centers will be their ability to help reverse the current trend in the United States of increasing adult mortality from prescription drug poisoning.⁶⁷ This chapter explores some of the critical roles of US poison centers and attempts to offer a vision of the future. An overview of the composition of poison centers worldwide can be found elsewhere.⁹⁶ Unique issues facing poison centers in other countries are discussed in Chap. 137.

The first toxicology database created in the United States was a set of cumbersome 5 × 8-inch index cards produced in the 1950s by the US National Clearinghouse of Poison Control Centers.¹⁰² When it grew to include more than 16,000 cards, the sheer volume of space required to store this information, and the extensive time necessary to manually search these cards, created the necessity of a central repository, such as a poison center. As available information grew, a rapid expansion of information technology occurred, and the unwieldy index card database was privatized and transformed into microfiche. Although this resource was physically smaller, specialized equipment was required, and a search was still time consuming. Numerous encyclopedic and clinical textbooks were written to supplement the database and provide resources for the office or the bedside. With the growth of the computer age and the Internet, the computer program known as POISINDEX was established to replace the microfiche format as the major source of data on the contents of innumerable household and industrial products, drugs, and plant and animal xenobiotics. POISINDEX also provides uniform management strategies for many potentially toxic exposures. Over the years many proprietary competitors to POISINDEX such as TOXINZ and TOXBASE have gained recognition as valuable tools. Additionally, open source programs such as WIKITOX provide free information to both health care professionals and members of the public.

With this evolution of information technology, poison centers are no longer perceived as the sole guardians of toxicology information. Although these services are still essential for the public at large, and those professionals away from their computers or smart phones, a predictable decline in poison center utilization has paralleled this growth in availability of information. A 1991 study in Utah demonstrated that 82.6% of emergency physicians who had POISINDEX available in their institutions no longer routinely consulted the poison center.²⁷ A similar 1994 New York study suggested that 76% of physicians who had POISINDEX in their emergency departments (EDs) perceived that this decreased their own use of their poison center.¹²¹ These studies suggest that poison centers were more likely to be called for patients with acute and symptomatic overdose and less likely to be contacted for chronic toxicity, asymptomatic patients, and adverse drug reactions.

An initial analysis might suggest that this is an acceptable trend for health care professionals in that it both allows physicians to respond more rapidly to patient needs and for poison centers to be more available to those individuals, especially non–health care professionals, who do not have access to this information system. In fact, one regional poison center model demonstrated that an integrated voice response (IVR) system effectively reduced human interactions for medication identification by more than one-half.⁷⁵ By extension, it might be suggested that both the public and health care professionals can easily access the same information as poison specialists, making the human interaction nearly obsolete. However, this practice of “not calling” not only undermines the efforts of poison centers to gather epidemiologic data (see later) but also creates an understanding gap. In other words, the interpretation of the data is as essential (or more essential) than the data itself. For example, some commonly used sources of toxicology information such as the Physicians’ Desk Reference and material safety data sheets occasionally provide information that may be inaccurate, potentially misleading, or severely limited.^19,56,87 Likewise, reviews of drug interaction programs designed for mobile devices demonstrated significant variability between individual programs and superiority of larger online resources.^5,37,94,97 Although POISINDEX routinely provides more accurate information regarding overdose, it is only updated quarterly, cannot be expected to adapt to ongoing epidemiologic trends such as regional variations in substance use, and is incapable of judging adequacy or communications or the subtleties contained in natural language.

The best source for essential new information is skilled professionals who specialize in poisoning. In addition, because most databases are designed to provide information about known entities, they perform poorly when dealing with unknown and unclear scenarios—especially long and complicated differential diagnoses. For example, consider the case of a clinician caring for a lethargic child whose only medication is Zantac syrup. After the other causes of altered mental status have been excluded, the clinician considers drug toxicity. Consultation with standard references suggests that altered consciousness would not be expected with use of this medication. However, a certified poison specialist at a regional poison center recognizes the potential for drug error, has the physician review the syrup bottle in question, and then calls the pharmacy where the drug was provided. The poison specialist learns that although the prescription was written for ranitidine (Zantac), the bottle actually contains cetirizine (Zyrtec syrup), which could account for the child’s symptoms.

Thus, although originally designed as providers of information, poison centers are in reality valued consultants, with staff members who not only provide content information but also interpret clinical material and link both to appropriate management strategies. This goal can only be achieved through rigorous training and certification and recertification criteria designed to provide valued up to date interactions with health care professionals. Access to computer programs can never be considered a substitute for a thoughtful human analysis. Computers do not recognize anxiety, inappropriate questions, and other subtle issues that can only be appreciated with human interactions.

Another illustrative example of the value of poison centers can be drawn from the use of flumazenil for benzodiazepine overdose (Chap. 74 and Antidotes in Depth: A22). Although it may easily be determined by anyone capable of using a resource that flumazenil is an antidote for benzodiazepine overdoses, many subtle characteristics of the patient or the overdose often contraindicate its use. A prospective study determined that when flumazenil was used before consultation with the poison center, contraindications were present in 10 of 14 (71%) cases, resulting in one serious adverse event.²² In the study mentioned earlier, although physicians with access to POISINDEX were less likely to call the poison center, 86.7% still felt that using the poison center to gain access to a physician toxicologist was a valued resource.²⁷ Many poison centers are linked with centers for poison treatment, which are health care facilities that can provide both bedside consultation and unique diagnostic and therapeutic interventions for a subset of patients with severe or complex poisoning.¹ The benefits of consultation are discussed later in Health Care Savings.

In 2011, poison centers in the United States interacted with the public and health professionals more than 3.5 million times.¹⁸ While the financial value of these interactions will be discussed in the section on health care savings below, two major limitations to the success of poison centers were highlighted by recent studies. The first, which should be intuitively obvious, stems from the fact that poison centers are remote from the patient and can, therefore, only make decisions based on the information provided to them. Although poison information specialists are highly skilled and use a variety of communication styles to obtain the most accurate information,⁴⁸ the quality of the information impacts on the utility of their recommendations. The greatest concern often is the estimation of the actual dose of an exposure. In a 3.5 year study of all children referred by a poison center to a health care facility for the determination of the presence of either a methanol or an ethylene glycol blood concentration because of the history of an exposure, only 21 of 102 children had a measurable concentration.⁷⁸ While this has serious limitations on the interpretation of poison center data,⁶² the implications for clinical care are even greater. Likewise a human volunteer study demonstrated that adults are totally incapable of determining residual volumes in containers or describing the actual volume of semiquantitative descriptors such as “a small mouthful” or “a gulp.”⁶¹ Because critical decisions are made based on the history of ingestion or amount ingested, a clear challenge for poison centers is to develop methods to improve the accuracy of this information. Digital imagery may provide a useful method of assisting caregivers with determination of residual container volumes by allowing specialists to clarify container sizes and residual volumes.

The second challenge involves the gap that exists between recommendations that are made by poison centers and those that are accepted. Two recent papers highlight this concern. In a 7 year analysis of poison center recommendations for the administration of high dose insulin and glucose therapy, the recommended treatment was actually administered only 50% of the time.⁴⁹ Similarly, in a 5.5 year study of calcium channel blocker and β-adrenergic antagonist overdoses at a different poison center, high dose insulin and glucose therapy was only started in 42% of cases where it was recommended, and intravenous fat emulsion was only given in 33% of cases where it was recommended.⁴¹ Because both these therapies are considered effective and potentially life saving (Antidotes in Depth: A17 and A20), ­poison centers need to evaluate the reasons these recommendations are not accepted and explore methods to improve communication with providers. The use of on-site medical or clinical toxicology faculty liaisons may help reduce these gaps.

In 2007, the US Centers for Disease Control and Prevention (CDC) reported that poisoning fatality surpassed both motor vehicle crashes and firearms to become the leading cause of injury related fatalities.⁹³ This trend has continued and is largely influenced by an epidemic of prescription opioid abuse.⁶⁷ Understanding the evolving trends in poisoning is essential to the development of enhanced surveillance, prevention, and education programs designed to improve medication prescribing, drug safety, and to reduce unintentional poisoning. Although data can be analyzed from numerous sources, such as death certificates, hospital discharge coding records, and poison centers, it is essential to recognize the biases that are inherent in each of these reports. Because not all significant poisonings result in either hospitalization or fatality, data from poison centers appear to offer a unique perspective.

Unfortunately, the term “poisoning” is often defined differently and therefore may be confusing. In this text, “poisoning” is used to denote any exposure to any xenobiotic (drug, toxin, chemical, or naturally occurring substance) that results in injury. Yet the data collected and disseminated by poison centers are defined by the term “exposures.”^{13, 14, 15, 16, 17, and 18,76,117, 118, and 119} Many exposures are of limited toxicologic consequence either because of the properties of the xenobiotic involved, the magnitude or duration of the exposure, or the uncertainties regarding whether an actual exposure has occurred. Therefore, data collected by poison centers represent a limited and ill-defined measure of poisoning.

The situation is further confounded by multiple biases that are introduced by the actual reporting process, which first and foremost is voluntary and passive. Because most calls concern self reported data from the home and are never subsequently confirmed, a significant percentage of the data generated to date may actually represent only potential or possible exposures, which can introduce large statistical errors into the database. This is highlighted by the 21 of 102 children who tested positive for a toxic alcohol discussed above.⁷⁸ Despite the fact that only those 21 children were definitively exposed and potentially poisoned, all 102 were entered into the database as exposures. If these figures are representative of the rest of the data set, then they suggest that an actual ingestion does not occur in the vast majority of reported unintentional exposures in children. However, they do emphasize that in all of the cases a toxin was in an unacceptably close proximity to a child. Also, current events, hoaxes, and media awareness campaigns all may influence self-reporting rates.⁸¹ Furthermore, to report a possible exposure a caller must have a telephone, probably speak English, and have some degree of health literacy and numeracy.^80,115 Although telecommunications devices for the hearing impaired and translation services exist, they are rarely used. Enhancement of technology to facilitate the accurate exchange of information between poison specialists and either hearing impaired callers or those who do not speak English is essential to the success of poison centers. While text message is an interesting option, preliminary data suggest that text messaging encounters take way too long to be productive.⁹⁹ Another would be to entertain more active reporting systems automatically triggered directly by hospital laboratory values. Such a system would explore cognitive behavior of clinicians around reporting and develop a true understand of the epidemiology.

Under the present passive system, when hospitals report exposures to the poison center, a comparison of the hospital chart with the poison center record shows good agreement, demonstrating an accurate exchange of information.⁶⁴ Unfortunately, a reporting bias similar to that described above is well recognized regarding professional utilization of poison centers and has been called the Pollyanna phenomenon.⁵⁷ For example, in the spring of 1995, poison centers in the northeast United States began to receive numerous reports of severe psychomotor agitation and other manifestations of anticholinergic syndrome in heroin users. In the initial phase of the epidemic, most of the callers requested assistance in establishing a diagnosis, determining possible etiologies, and raised questions regarding treatment with physostigmine.⁵⁸ Although the epidemic continued for many months, once the media announced that the heroin supply was tainted with scopolamine, and clinicians became familiar with the indications and administration of physostigmine, call volume decreased. Stated simply, health care professionals are less likely to call the poison center regarding issues with which they are familiar, are of little clinical consequence, or are not recognized as being related to a poison. Thus, a bias is introduced that results in a relative over reporting of new and serious events and a relative underreporting of the familiar or very common, unrecognized poisoning, and those exposures or poisonings that are apparently inconsequential. Numerous comparisons support this contention. Investigators who rely on published data from poison centers as a sole source of epidemiologic information demonstrate a failure to understand the complexity of poisoning data and the aforementioned consequential limitations of poison center–derived data.

Fatal Poisoning

A 4 year study compared deaths from poisoning reported to the Rhode Island medical examiner with those reported to the area poison center.⁷⁹ Not surprisingly, the medical examiner reported many more deaths: 369 compared with 45 reported by the poison center. Although most of the cases not reported to the poison center were victims who died at home, were pronounced dead on arrival to the hospital, or those in whom poisoning was not suspected until the postmortem analysis, 79 patients who subsequently became unreported fatalities were actually admitted to the hospital with a suspected poisoning. In 10 of these cases, the authors concluded that a toxicology consultation might have altered the outcome. Examples of interventions that, if recommended and performed, might have resulted in a more favorable outcome included the proper use of antidotes such as naloxone for an opioid overdose, N-acetylcysteine for acetaminophen (APAP) poisoning, the cyanide antidote kit, sodium bicarbonate for a cyclic antidepressant overdose, hyperbaric oxygen for carbon monoxide poisoning, hemoperfusion for a theophylline overdose, and hemodialysis for a lithium overdose. While the xenobiotics may have changed since this study was performed, the fundamental principles highlighted remain relevant.

Likewise, when medical examiner data were analyzed in Massachusetts, more than 47% of poison fatalities had not been reported to the poison center.¹⁰⁷ A California study evaluating 358 poisoning fatalities reported to the medical examiner showed that only 10 poison center fatalities were reported over a similar time period, demonstrating an even more consequential reporting gap.⁷ Once again in this study, whereas the majority of underreporting was with respect to prehospital deaths (68%), only 5 of 113 hospitalized patients who ultimately died were reported to the poison center. Additionally, a cross-sectional comparison of national mortality data with poison center data for agricultural chemical poisoning demonstrated a similar trend of underreporting to poison centers of seriously poisoned admitted patients who became fatalities.⁷² Furthermore, when data for an entire year from the National Center for Health Statistics were compared with the same year of data from the American Association of Poison Control Centers (AAPCC), it was apparent that the AAPCC data captured only about 5% of annual poison fatalities.⁶³

More recent analyses have highlighted a remarkable trend. When 11 states evaluated trends in poison-related mortality from 1990 to 2001, an average increase of 145% was noted.¹⁰⁶ A more comprehensive investigation of the National Vital Statistics System accessed via the CDC’s Web-based Injury Statistics Query and Reporting System database demonstrated a 5.5% increase in injury related mortality from 1999 to 2004. Mortality from poisoning accounted for 61.9% of the increase in unintentional injury, 28% of the increase in suicide, 81.2% of the increase in death from undetermined intent, and more than half of the total increase injury-related mortality.⁹³ As of 2004, death from poisoning surpassed firearms and became the second most common cause of injury-related fatality. While most of the fatalities are in adults, a review of the entire 2010 AAPCC database only found 74 reported fatalities in children.²³ Focusing on poison center data alone would produce the erroneous assumption that poisoning-related fatalities were not a significant public health concern. In actuality, poisoning is a significant concern in that other programs designed to reduce deaths from motor vehicle crashes and firearms have been largely successful whereas decades have gone by without a major intervention targeting poison related fatality.

It is logical to assume that similar disparities exist regarding the reporting of nonfatal poisonings. The resultant gap in public health data needs to be addressed through improved definitions, epidemiology, reporting, and analysis of poison-related data systems. This inequity has developed through a long-standing tradition of poison centers to focus attention and concentrate on the largely benign exposures in children. The emphasis needs to be redirected toward seriously ill poisoning, utilization of the intensive care unit, and other markers of actual poisoning rather than health care utilization for benign events. The necessary data for such an evaluation may already exist, but the challenge will be in linking the data sets to provide a meaningful analysis.

Nonfatal Poisoning

An outreach study in Massachusetts determined that hospitals geographically close to a poison center reported their cases almost twice as often as hospitals remotely located (46% vs. 27% of total cases).²⁸ Additionally, the authors noted that private physicians were less likely to report cases than residents in training. A one year retrospective review demonstrated that only 26% (123 of 470) of poisoned patients who were treated in a particular ED were reported to the poison center.⁵⁹ Interestingly, only 3% of inhalational exposures were reported, compared with 95% of cyclic antidepressant ingestions. The authors also noted, as suggested above, that reporting decreased when comparable exposures occurred over a short period of time. Finally, in the physician survey study cited earlier, physicians reported that they would “almost never” contact the poison center for asymptomatic exposures (62.9%), chronic toxicity (50.4%), or simply to assist in establishing a reliable database (90.2%).²⁷ This statement is most likely accurate even in jurisdictions in which the reporting of all or select exposures is incorporated into public health laws.

Occupational Exposures

Xenobiotic exposure occurs commonly in the workplace. As a result of the long-recognized association between occupational exposure and illness, several federal and state government funded agencies, such as the National Institute for Occupational Safety and Health, Occupational Safety and Health Act, and the Agency for Toxic Substances and Disease Registry (ATSDR), exist to prevent occupational illness, to educate the public, and to collect data on exposures to occupational xenobiotics. Legislation provides for mandatory reporting in some instances and offers workers job protection for voluntary reporting. Poison centers also provide information on occupational exposures and collect data. Once again, there are discrepancies between the poison information data and the data collected by governmental agencies. A six month survey in California noted that only 15.9% of the occupational cases reported to the poison center were captured by a state occupational reporting system.⁹ The most common occupational toxicologic illness—dermatitis—was even further underrepresented in these cases. A follow-up study by the same authors demonstrated that more than one-third of calls came directly from the individual worker, 70% of whom were unaware of the link between their occupation and their symptoms.⁸ Although these data suggest that poison centers can provide substantial assistance following occupational exposures, one author expressed concern, noting in a follow-up study that the poison center failed to provide an adequate epidemiologic assessment in that it did not identify an average of 12 other people per workplace who were also potentially exposed in addition to the index case.¹¹ A 1999 survey of poison centers concluded that “responses to work-related calls are inadequate” and suggested that written protocols might be helpful.¹²

Adverse Drug Events and Xenobiotic Errors

Although the actual numbers are a source of controversy, data suggest that a striking number of adverse drug events (ADEs) occur each year in the United States, with many resulting in death.^20,31,77 The ease of 24 hour telephone access, combined with the ability to consult with a health professional, make poison centers ideal resources for reporting of ADEs.³⁰ Yet, more than 76% of physicians surveyed stated that they would “almost never” contact the poison center regarding adverse drug events.²⁷ Moreover, 30 of the 56 (53.6%) poison centers surveyed stated that they had not submitted any of their ADE data to the US Food and Drug Administration’s MedWatch program.³⁴ Many of the other centers reported only partial compliance with the MedWatch system.³⁴ Biases may lead to disproportionate reporting of adverse events related to newer drugs skewing the interpretation of the data. For example, although bleeding may occur from both coumadin and dabigatran, it is easy to believe that reports would be more likely to be generated for the newer drug.

Prescription drug errors are another source of potential poisoning. Retrospective review of poison center data suggests that many of these errors are reported. In one report, the poison center provided valuable feedback to pharmacists and physicians about these errors. Ideally, reporting to the state board of pharmacy would assure that proper surveillance and counseling continue. The poison center would seem to be ideally suited to perform this function.¹⁰⁴ Unfortunately, while pharmacists are ideally positioned to identify prescribing errors, data suggest that pharmacist utilization of poison centers is poor.²

Drugs of Abuse

Poison centers also collect data on exposures to drugs of abuse and misuse. These data consist largely of calls for information from the concerned public and reports of overdose requiring health care intervention. Although ethanol, tobacco, and caffeine are the most common xenobiotics used in society, these cases are rarely reflected in poison center data, with the exception of unintentional exposures in children. In fact, because most substance abuse does not result in immediate interactions with the health care system, other databases such as the National Institute of Drug Abuse Household Survey (now referred to as the Monitoring the Future Study) might better reflect substance abuse trends. Yet even this database has significant limitations.^6,54 Because poison centers are more focused on immediate health care effects of exposures, it could be argued that only those cases in which health care interaction is required are of value in the database. Since poison centers collect data in real time, centers are ideally positioned to report on emerging trends and sentinel events. Recent examples include poison center experiences with trends opioid abuse in teenagers,^51,111 bath salts,⁸⁸ synthetic cannabinoid receptor agonists,⁸⁹ and adulterated cocaine.¹¹²

Grossly Underreported Xenobiotics

As discussed previously, there is little doubt that ethanol and tobacco are the most common xenobiotics intentionally used in our society. Although their toxicologic manifestations can be acute and severe, chronic subcl­inical poisoning often goes unnoticed for many years. Similarly, more than 500,000 American children have lead concentrations above 10 μg/dL and polychlorinated biphenyls can be found in countless adults and children. We must remain cognizant of these large-scale exposures, such as bisphenol A, when we read that plants, cleaning products, and cosmetics comprise the most common exposures to xenobiotics¹⁸ are the most commonly “reported” exposures.

Integrating Epidemiologic Data as Part of the Public Health Surveillance System

With the current limitations of the poison center data, it should be clear that neither the numerator nor the denominator of the actual number of poisonings can be easily appreciated. However, analysis of these data for trends may be more useful because the inherent biases involved in poison center reporting are probably consistent over many years. Increasingly, poison center data are being used as part of surveillance and prediction models,^46,123 often that extend beyond poisoning to other public health concerns.¹⁰⁵ Rapid reporting in collaboration with the CDC highlights an essential partnership.^38,55,89 Efforts should be directed to encourage reporting to poison centers by such enhanced access methods as Web-based forms for passive reporting, a direct interface between laboratory and hospital databases that actively transmits data to poison centers, and linkages to other agencies that collect reports of poisoning such as state and local health departments. Additional resources should be directed at improved case definitions (distinguishing asymptomatic exposure from poisoning) and integration with other essential databases such as MedWatch, the National Vital Statistics System, and the National Center for Health Statistics.

Despite its limitations, poison center data have significant utility. It is often an exposure rather than an actual poisoning that provides the impetus for contact with health care. For those exposures that are unlikely to be consequential, the poison center can intervene to prevent potentially harmful attempts at home decontamination and costly unnecessary visits to health care professionals. Interaction with parents at a time of perceived crisis also provides a “teachable moment” (Chap. 135) that may help prevent a more consequential exposure in the future. For those exposures that may result in poisoning, the period of time immediately following exposure is an ideal moment to initiate first aid measures designed to prevent or lessen the severity of poisoning. For both of these reasons the cost, benefits, and efficacy of poison centers especially regarding home calls must be measured in terms of exposures and not poisonings.

When visits to pediatric EDs for acute poisoning were analyzed, one study demonstrated that 95% of parents had not contacted the poison center before coming to the hospital and 64% of those children required no hospital services and could have therefore profited from a poison center interaction.²⁹ By contrast, when parents called the poison center first, fewer than 1% sought emergency services afterward. When 589 callers to one poison center were surveyed, 464 (79%) stated that they would have used the emergency care system if the poison center were unavailable.⁶⁹ In a similar study, 36% of callers would have selected a more costly alternative if the poison center were unavailable.¹⁰ Likewise, when primary care givers were surveyed, over 80% said that they would activate 9-1-1 if there were no poison center.³ Poison center data confirm that approximately 75% of reported exposures that originate outside of health care facilities can be safely managed onsite with limited telephone follow-up. Suggesting simple techniques or reassurance can successfully reduce hospital visits for patients who typically call poison centers which, as defined, may only represent a potential exposure. The use of established protocols, especially for unintentional exposures in children clearly reduces emergency department referral rates.⁶⁰ These interactions can be followed by distribution of simply written prevention literature to improve use and retention. Unfortunately, this approach is less applicable to adults and the population as a whole.

Limited data suggest that direct bedside consultation and care help reduce length of hospital stay and health care costs.³⁶ Yet poison centers operate remotely. In one assessment, consultation with a poison center reduced length of stay by nearly 3 days.¹¹⁴ Similarly, when the poison center was consulted for patients already in the hospital, length of stay and costs were reduced by 1.9 days and nearly $5000.²¹ This experience has been replicated outside the United States where poison center consultation resulted in a decreased length of stay of more than 3 days, respectively.⁵² Strongly encouraged or mandated interactions with poison centers might help reduce the cost of health care, hospital overcrowding, and access to limited resources such as antidotes and hemodialysis.

The national average cost to the poison center for a single human exposure call is on the order of $35.¹²⁵ A federally funded study concluded that, in one year, poison centers reduced the number of patients who were treated but not hospitalized by 350,000 and reduced hospitalizations by an additional 40,000 patients, for a cost savings of more than $3 million in 1996 dollars.⁸⁶ Each call to a poison center prevented at least $175 in subsequent medical costs, providing strong theoretical evidence to support the cost efficacy of poison centers. In fact, two natural experiments support these calculations. In 1988, Louisiana closed its state sponsored poison center. During the year that followed, the cost of emergency medical services for poisoning in Louisiana increased by more than $1.4 million. This additional expenditure represented a greater than threefold increase above the operating cost of that center.⁷¹ Similarly, because of financial disputes in California, direct access to the San Francisco poison center was electronically restricted for one major county, with a telephone recording referring callers instead to the county 9-1-1 system for assistance.⁹⁵ The result of each blocked call was to increase health care costs by approximately $33. Moreover, these calculations cannot account for the unmeasured benefits to society from poison center interventions that reduce waiting times for ambulance availability and hospital treatments because of lower volumes, money saved by the prevention or reduction of injury from early intervention, or lives saved by enhancing access to or utilization of the health care system for seriously poisoned patients. In El Paso TX, cooperation between emergency medical services and the poison center was able to reduce ambulance dispatches by 1750 over 5 years.⁴ Overall estimates place the rate of return for poison center funding between 11 and 36:1.^66,108

However, many barriers prevent a person from calling a poison center, including lack of familiarity with its available services, intellectual and cultural factors, language difficulties, and confidentiality concerns.^35,70,80,115 Epidemiologic studies demonstrate that areas of increased population density, such as major urban communities, with high percentages of minority inhabitants have lower utilization of poison center services.¹¹³ Additional barriers include the absence of caregiver comfort with the extensive personal contact provided by the health care system and a concern regarding implications of child abuse or neglect when reporting to agencies such as poison center, many of which have governmental ties.¹⁰³ Data demonstrate that public educators can help overcome some of these barriers.¹⁰⁹ One good example of an effort to overcome reporting barriers was the institution of a single national toll-free number for poisoning (1-800-222-1222). Although it is clear that this intervention improved access and increased total calls to the poison center,⁷⁴ it has yet to be determined if this has altered the patterns of use.

Poison center staff work closely with physicians, community health educators, community support groups, and parent–teacher associations to develop poison prevention activities.⁸²Table 136–1 lists common strategies advocated to prevent poisoning. Poison centers are also actively involved in enhancing training programs for paramedics,⁴⁷ medical students,⁶⁸ pharmacy students,⁴⁰ and resident physicians,^40,91,122 and are an integral part of postgraduate training programs in medical toxicology fellowships.

As stated previously, there is an inherent risk in both enhanced public and professional education programs. Currently, the decreased telephone utilization of a poison center could be both the result of a decrease in the incidence of exposures or poisonings or an enhanced understanding of the prevention, diagnosis, and treatment of poisoning. Although education should never be viewed as detrimental, programs must include an emphasis on the continued use of poison centers to assure access to most current information in a rapidly changing discipline that only develops through an ongoing dialog between health care professionals and poison specialists. In actuality, as a result of the ongoing analysis of incoming calls, the knowledge base has the potential to change as rapidly as the calls are reported. This is far more rapid than can occur in any published literature or electronic database. Thus, additional emphasis should be applied to routine utilization of the poison center as a public health tool to improve the accuracy of epidemiologic data. Reporting of rare or suspected events can serve as sentinel efforts that help identify consequential adverse drug opportunities long before normal postmarketing surveillance tools identify areas of concern.

On the other hand, outreach programs that advise the public to access free services for inconsequential events can easily overwhelm an already stressed system of responding to incoming calls by demanding an immediate response to the less serious calls in an appropriate time frame. Public education and public health must both be considered to assure that poison centers are staffed with the appropriate number of skilled individuals to respond not only to daily events, but also to address surges in calls that may be the result of true epidemics or responses to media announcements. Increasing calls to demonstrate increased utilization offers no public health advantage if the utilization is inappropriate or if seriously ill or potentially ill callers lose access to timely responses.

The initial public health efforts of poison centers focused on attempts to alter product concentration and to enhance product labeling and packaging. These clearly beneficial endeavors should continue and must evolve. However, current events have also increased poison center activities in preparedness for mass gatherings and disasters resulting from radiological, biological, and chemical terrorism.^53,73 Additional links with governmental agencies such as the CDC and ATSDR will expand the role of medical toxicology in community health. The need for 24 hour rapid access to centralized information, existing data entry and retrieval systems, and links to experts in medical toxicology and emergency medicine helps to place poison centers in critical roles in both local and national initiatives. Important contributions have included development of triage and treatment protocols^{24, 25, and 26,32,33,39,43,60,83, 84, and 85,90,92,100,101,120,124} and assessments of antidote supplies.^42,44,45Table 136–2 summarizes initiatives that require creation or enhancement to improve poisoning epidemiology data. Many of these are discussed extensively in a report from the Institute of Medicine.⁶⁵

• Public education efforts help reduce the likelihood of exposure.

• Provision of basic management advice helps to diminish the consequences of a poisoning once an exposure has occurred.

• Reassurance and proper basic management help to curtail unnecessary utilization of expensive health care.

• Interactions with health care professionals streamline the care of poisoned patients saving hospital days and health care expenditures.

• Collaboration with public health authorities will identify, inform, and help mitigate the consequences of ongoing toxicologic events.

• Data on exposures have been effective to create legislation to further limit poisoning by altering contents or improving packaging or labeling.

Acknowledgment

Richard S. Weisman, PharmD, contributed to Table 136–1 in previous editions.

References