A guide to interpreting economic studies in infectious diseases.

Healthcare providers continue to seek improved methods for preventing, detecting and treating diseases that affect human survival and quality of life. At the same time, there will always be financial constraints because of limited societal resources. Many of the discussions on how to provide economically sound solutions to this challenge have not fully engaged the input of clinicians in the field. The purpose of this review is to increase economic knowledge for clinicians. We cover healthcare cost elements and methods used to assign value to a health outcome. We outline the challenges in conducting economic studies in the field of infectious diseases. Finally, we discuss the meaning of efficiency from multiple perspectives, and how the concept of economic externalities applies to infectious diseases.

The role of neural activity in the migration and differentiation of enteric neuron precursors.

BACKGROUND: As they migrate through the developing gut, a sub-population of enteric neural crest-derived cells (ENCCs) begins to differentiate into neurons. The early appearance of neurons raises the possibility that electrical activity and neurotransmitter release could influence the migration or differentiation of ENNCs. METHODS: The appearance of neuronal sub-types in the gut of embryonic mice was examined using immunohistochemistry. The effects of blocking various forms of neural activity on ENCC migration and neuronal differentiation were examined using explants of cultured embryonic gut. KEY RESULTS: Nerve fibers were present in close apposition to many ENCCs. Commencing at E11.5, neuronal nitric oxide synthase (nNOS), calbindin and IK(Ca) channel immunoreactivities were shown by sub-populations of enteric neurons. In cultured explants of embryonic gut, tetrodotoxin (TTX, an inhibitor of action potential generation), nitro-L-arginine (NOLA, an inhibitor of nitric oxide synthesis) and clotrimazole (an IK(Ca) channel blocker) did not affect the rate of ENCC migration, but tetanus toxin (an inhibitor of SNARE-mediated vesicle fusion) significantly impaired ENCC migration as previously reported. In explants of E11.5 and E12.5 hindgut grown in the presence of TTX or tetanus toxin there was a decrease in the number nNOS+ neurons close to the migratory wavefront, but no significant difference in the proportion of all ENCC that expressed the pan-neuronal marker, Hu. CONCLUSIONS & INFERENCES: (i) Some enteric neuron sub-types are present very early during the development of the enteric nervous system. (ii) The rate of differentiation of some sub-types of enteric neurons appears to be influenced by TTX- and tetanus toxin-sensitive mechanisms.

The observation unit: a new interface between inpatient and outpatient care.

PURPOSE: Observation units for patients who present to emergency departments with chest pain have become common. We describe our 3-year experience with a multipurpose observation unit in which chest pain accounts for only a minority of patients' presenting clinical syndromes. SUBJECTS AND METHODS: We analyzed the effects of a 12-bed observation unit on inpatient admissions for common clinical syndromes, as well as its overall effects on inpatient medical admissions during its first 3 years of operation (1996 to 1998) compared with the 3 years preceding its creation (1993 to 1995). RESULTS: Among 7,507 patients admitted to the observation unit in 1996 to 1998, 6,334 (85%) were discharged home within 23 hours. Total inpatient medical admissions fell by a similar number (n = 5,366) during the 3 years of operation of the observation unit when compared with the 3 preceding years (39,569 admissions in 1996 to1998 versus 44,935 in 1993 to 1995). Analysis of local area trends suggested that the use of the observation unit contributed to reduced hospital admissions, rather than vice versa. CONCLUSION: Observation units can serve patients with diverse clinical syndromes and may reduce inpatient admissions. This novel "point of care" deserves further evaluation.

Determining which patients require evaluation for blunt cardiac injury following blunt chest trauma.

The objective of this study was to determine prospectively which risk factors require cardiac monitoring for blunt cardiac injury (BCI) following blunt chest trauma. All patients who sustained blunt chest trauma had an electrocardiogram (ECG) on admission to our urban level I trauma center. Those with ST segment changes, dysrhythmias, hemodynamic instability, history of cardiac disease, age > 55 years, or a need for general anesthesia within 24 hours (group 1) were admitted to the intensive care unit (ICU) for 24 hours where they were subjected to serial ECGs, creatinine phosphokinase (CPK) assays, and echocardiography (ECHO). Those with only mechanism for BCI, i.e., none of the above risk factors (group 2), were admitted to a nonmonitored bed and had a follow-up ECG 24 hours later. A series of 315 patients were admitted with blunt chest trauma during a 17-month period; 144 patients were in group 1 and 171 in group 2. Overall, 22 patients were diagnosed as BCI (+BCI), defined as evolving ST segment changes, dysrhythmias, a CPK-MB index of > 2.5, or hemodynamic instability. Of the 18 +BCI patients in group 1, all were symptomatic (i.e., none was included solely for a cardiac history, age, or need for general anesthesia). Six of these patients required treatment for dysrhythmias, hypotension, or pulmonary edema; one of whom died. Four patients with +BCI were in group 2 and had ECG changes at 24 hours; none of these four had any sequelae from their +BCI. None of the ECHOs demonstrated abnormal wall motion. Patients who sustain blunt chest trauma with a normal ECG, normal blood pressure, and no dysrhythmias on admission require no further intervention for BCI. Patients with ST segment changes, dysrhythmias, or hypotension following blunt chest trauma should be monitored for 24 hours, as this subgroup occasionally requires further treatment for complications of BCI. ECHO adds nothing as a screening test.

Prognosis of penetrating trauma in elderly patients: a comparison with younger patients.

BACKGROUND: It has previously been shown that elderly patients have a worse prognosis than their younger counterparts after sustaining blunt trauma. This is due in part to a higher incidence of comorbid conditions as well as less physiologic reserve in an elderly population sustaining largely blunt trauma. We compared the outcome after penetrating trauma in elderly patients to matched "younger" patients to determine whether they had a similarly poor prognosis. METHODS: Elderly patients (> or = 65 years) were identified from our trauma registry. Sex, mechanism of injury, and Abbreviated Injury Score/Injury Severity Score were determined from the registry. Patients presenting with traumatic arrest were excluded. The registry was then searched for patients aged 15 to 40 years with the same sex, mechanism of injury, and Abbreviated Injury Score in each region. A chart review was then performed to determine additional details of their hospital stay. The two groups were then compared using Student's t test and Fisher's exact chi2 test, as appropriate. RESULTS: Eighty-five elderly patients (OLD group) were admitted with penetrating trauma between 1983 and 1998. They were compared with 85 matched young patients (YOUNG group). Each group included 66 male and 19 female patients. In each group, gunshot wounds occurred in 45.9%, stab wounds in 52.9%, and shotgun wounds in 1.2% of patients. The average Injury Severity Score in each group was 5.5 +/- 5.6 (range, 1-29) and the regional Abbreviated Injury Scores were likewise equal in both groups. The OLD patients had an average hospital stay of 6.9 +/- 9.1 days compared with 4.3 +/- 5.7 days in the YOUNG patients (p < 0.05). Twenty-seven OLD patients spent 7.3 +/- 9.2 days in the intensive care unit compared with 19 YOUNG patients who stayed 3.4 +/- 3.2 days (p < .05). A total of 91 comorbidities were identified in 58 OLD patients compared with 18 in 15 YOUNG patients (p < .0001). Eighty-six invasive procedures were performed in the OLD group compared with 96 in the YOUNG group (p = not significant). Nineteen OLD patients (22.3%) and 15 YOUNG patients (17.6%) suffered one or more complications, including death (p = not significant). A total of 91% of surviving OLD patients were discharged to home compared with 100% of surviving YOUNG patients (p < .01). CONCLUSION: Elderly patients who sustain penetrating trauma have more comorbidities than their younger counterparts. This may account for their longer hospital stay and lesser ability to be discharged home. These patients do not have an increased complication rate and should continue to be managed aggressively.

Experience with over 2500 diagnostic peritoneal lavages.

This study was undertaken to confirm the safety and efficacy of diagnostic peritoneal lavage (DPL) for trauma patients. A prospectively maintained database of all DPLs performed in the past 75 months was analyzed. A red blood cell count of 100,000/mm(3) was considered positive for injury in blunt trauma; 10,000/mm(3) was considered positive for peritoneal penetration in penetrating trauma. Information relative to type of injury, DPL result, laparotomy result and complications, was analysed to determine if DPL was more or less suited to any specific indication or type of patient. Over a 75 month period, 2501 DPLs were performed at our urban level I trauma center. The overall sensitivity, specificity and accuracy for the above thresholds were 95, 99 and 98%. The majority (2409, 96%) were performed using percutaneous or "closed" seldinger technique. Ninety-two (4%) were performed using open technique because of pelvic fractures, previous scars and pregnancy. Open DPL was less sensitive than closed DPL in patients who sustained blunt trauma (90 vs 95%) but slightly more sensitive in determining penetration (100 vs 96%). Overall, there were 21 complications (0.8%). There was no difference in complication rate between open and closed DPL. In conclusion, DPL remains a highly accurate, sensitive and specific test with an extremely low complication rate. It can be performed either open or closed with comparable results. We recommend its use in the evaluation of both blunt and penetrating trauma.

Enaminones-versatile therapeutic pharmacophores. Further advances.

Enaminones, enamines of ss-dicarbonyl compounds, have been know for many years. In our initial account (Current Med. Chem. 1994, 1, 159-175), we reported on the anticonvulsant activity of a series of enaminones, notably methyl 4-[(p-chlorophenyl)amino]-6-methyl-2-oxo-cyclohex-3-en- 1-oate, 9a (R=CH3, R1=4-Cl), which, in animal tests, compared favorably to phenytoin and carbamazepine. Since that time, further research in our laboratory and other laboratories have expanded the therapeutic potential of these compounds. In addition to new anticonvulsant derivatives, we have uncovered a novel brain transport mechanism for the enaminones and developed a preliminary regression model for further synthetic direction. These topics will each be presented and elaborated.

Patient satisfaction with an emergency department asthma observation unit.

OBJECTIVE: To compare levels of patient satisfaction between the diagnostic and treatment protocols in an ED-based asthma observation unit (AOU) and those with standard inpatient hospitalization. METHODS: This was a prospective, randomized, controlled trial with a sample of 163 patients presenting to the ED with acute asthma exacerbations over a 30-month period. Eligible patients were those who could not resolve their symptoms after three hours of standard ED therapy. Patients were then randomly assigned to an ED-based AOU (experimental group) or to customary inpatient care (control group). Patient satisfaction and problems with care processes were assessed by standardized instrumentation at discharge in both groups. RESULTS: The AOU patients scored higher than those randomized to the inpatient hospitalization protocol on four summary ratings of patient satisfaction measures: received service wanted, recommendation of the service to others, satisfaction with the service, and overall satisfaction. The AOU patients reported fewer total number of problems with care received, and fewer specific problems with communication, emotional support, physical comfort, and special needs, than did the inpatient group. However, the AOU patients reported more problems regarding their knowledge of financial costs and liabilities for their service than did the inpatients. CONCLUSION: Patients were more satisfied and had fewer problems with rapid diagnosis and treatment in the AOU than they did with routine inpatient hospitalization. Since AOUs represent a new ambulatory service modality, patients would benefit from greater awareness of the costs and coverage for AOUs as compared with hospital inpatient care. These findings have important implications for the future short- and long-term success and feasibility of ED-based AOUs.

The utility of head computed tomography after minimal head injury.

OBJECTIVE: To determine if patients who present with a history of loss of consciousness who are neurologically intact (minimal head injury) should be managed with head computed tomography (CT), observation, or both. METHODS: We prospectively studied patients who presented to our urban Level I trauma center with a history of loss of consciousness after blunt trauma and a Glasgow Coma Scale score of 15. All patients underwent CT of the head and were subsequently admitted for 24 hours of observation. RESULTS: A total of 1,170 patients with minimal head injury were studied during a 35-month period. All patients had Glasgow Coma Scale scores of 15 on arrival and had a history of either loss of consciousness or amnesia to the event. Two hundred forty-seven patients (21.1%) were intoxicated with drugs or alcohol on admission; 39 patients (3.3%) had abnormalities detected by CT, including 18 intracranial bleeds; 21 patients (1.8%) had changes in therapy as a direct result of their CT results, including 4 operative procedures. No patient with negative CT results deteriorated during the subsequent observation period. CONCLUSION: CT is a useful test in patients with minimal head injury because it may lead to a change in therapy in a small but significant number of patients. Subsequent hospital observation adds nothing to the CT results and is not necessary in patients with isolated minimal head injury.

Distribution of variable vs fixed costs of hospital care.

CONTEXT: Most strategies proposed to control the rising cost of health care are aimed at reducing medical resource consumption rates. These approaches may be limited in effectiveness because of the relatively low variable cost of medical care. Variable costs (for medication and supplies) are saved if a facility does not provide a service while fixed costs (for salaried labor, buildings, and equipment) are not saved over the short term when a health care facility reduces service. OBJECTIVE: To determine the relative variable and fixed costs of inpatient and outpatient care for a large urban public teaching hospital. DESIGN: Cost analysis. SETTING: A large urban public teaching hospital. MAIN OUTCOME MEASURES: All expenditures for the institution during 1993 and for each service were categorized as either variable or fixed. Fixed costs included capital expenditures, employee salaries and benefits, building maintenance, and utilities. Variable costs included health care worker supplies, patient care supplies, diagnostic and therapeutic supplies, and medications. RESULTS: In 1993, the hospital had nearly 114000 emergency department visits, 40000 hospital admissions, 240000 inpatient days, and more than 500000 outpatient clinic visits. The total budget for 1993 was $429.2 million, of which $360.3 million (84%) was fixed and $68.8 million (16%) was variable. Overall, 31.5% of total costs were for support expenses such as utilities, employee benefits, and housekeeping salaries, and 52.4% included direct costs of salary for service center personnel who provide services to individual patients. CONCLUSIONS: The majority of cost in providing hospital service is related to buildings, equipment, salaried labor, and overhead, which are fixed over the short term. The high fixed costs emphasize the importance of adjusting fixed costs to patient consumption to maintain efficiency.

Acidosis and nutrition.

In recent years there has been increasing evidence for the deleterious effect of acidosis on a number of fundamental systems of the body including nutrition [1, 2]. Approximately 70 mmol of hydrogen ions are produced daily by the body, and to maintain acid-base balance there must be an equivalent net acid secretion by the kidney. It is remarkable that extracellular fluid (ECF) pH is maintained within a very narrow range of 7.35-7.45 (35-45 nM), reflecting the fundamental importance of pH on many aspects of basic cellular function particularly proteins. It is important to differentiate between the terms acidosis and acidemia. The former is a pathophysiologic process tending to acidify body fluids, whereas the latter occurs when the ECF hydrogen ion concentration is above the normal range. It is possible to be acidotic (with a reduced serum bicarbonate) but not acidemic because of appropriate buffering of hydrogen ions. The major extracellular buffer is the carbonic acid/hydrogen carbonate system with plasma proteins and hemoglobin contributing significantly less. The major intracellular buffer is protein followed by bone [3]. The type of acidosis seen in patients with chronic renal failure changes with decreasing GFR; initially a non-anion gap acidosis is observed secondary to the loss of bicarbonate from the proximal tubule and impaired excretion in the distal tubule. With increasing severity of renal impairment, failure to excrete organic and inorganic acids results in an increased anion gap [4, 5].

Emergency Department Observation Unit versus hospital inpatient care for a chronic asthmatic population: a randomized trial of health status outcome and cost.

OBJECTIVES: This study was designed to determine if an accelerated treatment protocol administered to acute asthmatics presenting to a Hospital Emergency Department Observation Unit (EDOU) can offset the need for inpatient admissions and reduce total cost per episode of care without sacrificing patient quality of life. METHODS: The authors used a prospective randomized controlled trial comparing postintervention patient quality of life for EDOU care versus standard inpatient care as measured by the standardized Medical Outcomes Study (MOS) SF-36 instrument. Other measures reported include: clinical status as measured by peak flow rates, total cost per treatment arm using microcosting techniques, and relapse-free survival 8 weeks after treatment. Eligible patients (n = 113) were assigned randomly to an EDOU or inpatient care from a consecutive sample of 250 acute asthmatic patients presenting to an urban hospital emergency department who could not resolve their acute asthma exacerbation after 3 hours of emergency department therapy. RESULTS: Patients assigned to the EDOU had lower mean costs of treatment (EDOU = $1,202 versus Hospital Inpatient = $2,247) and higher quality of life outcomes after intervention in five of eight domains measured by the MOS SF-36: Physical Functioning, Role Functioning-Emotional, Social Functioning, Mental Health, and Vitality. No differences were found in clinical outcomes as measured by peak flow rates or postintervention relapse-free survival. Univariate comparative findings were re-examined and confirmed through multivariable analysis when baseline SF-36 scores and postintervention peak expiratory flow rates clinical status were used as covariates. CONCLUSIONS: The study showed that the EDOU was a lower cost and more effective treatment alternative for a refractory asthmatic population presenting to the Emergency Department. Several baseline MOS SF-36 domains proved useful in predicting or validating posttreatment clinical status, relapse, and total costs of care. Outcome SF-36 domain scores were also useful in identifying patients with the most favorable clinical, cost, and relapse rate outcomes at the study endpoint.

Synthesis, characterization, and anticonvulsant activity of enaminones. Part 5: investigations on 3-carboalkoxy-2-methyl-2,3-dihydro-1H-phenothizin-4[10H]-one derivatives.

A new series of anticonvulsant 3-carboalkoxy-2-methyl-2,3-dihydro-1H-phenothiazin-4[10H]-on es is herein reported. 2-Aminothiophenols underwent cyclocondensation with 4-carboalkoxy-5-methylcyclohexane-1,3-diones in refluxing dimethylsulfoxide (DMSO) to yield 3-carboalkoxy-2-methyl-2,3-dihydro-1H-phenothiazin-4[10H]-on es, 4ak. In the case of the carbo-tert-butoxy derivatives (4c and 4k) prolonged reaction times led to the isolation of the respective 3-unsubstituted-2-methyl-2,3-dihydro-1H-phenothiazin-4[10H]-ones (41 and 4m) instead. Significant anticonvulsant activity was displayed by these analogues, most particularly 4k, which was active at 30 mg/kg intraperitoneally (ip) in mice in the maximal electroshock seizure (MES) evaluation, with no toxicity noted at dosages up to 300 mg/kg. Oral (p.o.) rat evaluation of 4k in the MES evaluation provided an ED50 of 17.60 mg/kg, with no toxicity noted at dosages up to 500 mg/kg, providing a protective index (PI = TD50/ED50) > 28.40. These compounds represent the first reported series of phenothiazines which possess anticonvulsant activity.

Routine preoperative "one-shot" intravenous pyelography is not indicated in all patients with penetrating abdominal trauma.

BACKGROUND: To determine which patients need a "one-shot" intravenous pyelogram (IVP) before laparotomy for penetrating abdominal trauma. STUDY DESIGN: Over a 15-month period, 240 laparotomies were performed for penetrating trauma at our urban level I trauma center. Prospectively collected data included clinical suspicion of genitourinary injury, results of preoperative IVP, intraoperative findings, and operative decisions influenced by the IVP. RESULTS: Preoperative IVP was performed in 175 patients (73%). Of these, 71 (41%) had suspicion of a renal injury based on the presence of a flank wound or gross hematuria. The IVP was believed to influence operative decisions in six patients, all in this group. Each of these six patients had either a shattered kidney or a renovascular injury and had a nephrectomy performed with the knowledge that a normal functioning kidney was present on the contralateral side. No patient without a flank wound or gross hematuria had an IVP that was judged to be helpful intraoperatively. Preoperative IVP was helpful only in patients with flank wounds or gross hematuria. Nephrectomy was performed in two additional patients who did not undergo IVP, both of whom presented in shock. CONCLUSIONS: Routine preoperative IVP is not necessary in all patients undergoing laparotomy for penetrating trauma. The number of IVPs can be safely reduced by 60% if the indications are narrowed to include only those stable patients with a flank wound or gross hematuria.

Costs of an emergency department-based accelerated diagnostic protocol vs hospitalization in patients with chest pain: a randomized controlled trial.

CONTEXT: More than 3 million patients are hospitalized yearly in the United States for chest pain. The cost is over $3 billion just for those found to be free of acute disease. New rapid diagnostic tests for acute myocardial infarction (AMI) have resulted in the proliferation of accelerated diagnostic protocols (ADPs) and chest pain observation units. OBJECTIVE: To determine whether use of an emergency department (ED)-based ADP can reduce hospital admission rate, total cost, and length of stay (LOS) for patients needing admission for evaluation of chest pain. DESIGN: Prospective randomized controlled trial comparing admission rate, total cost, and LOS for patients treated using ADP vs inpatient controls. Total costs were determined using empirically measured resource utilization and microcosting techniques. SETTING: A large urban public teaching hospital serving a predominantly African American and Hispanic population. PATIENTS: A sample of 165 patients was randomly selected from a larger consecutive sample of 429 patients with chest pain concurrently enrolled in an ADP diagnostic cohort trial. Eligible patients presented to the ED with clinical findings suggestive of AMI or acute cardiac ischemia (ACI) but at low risk using a validated predictive algorithm. MAIN OUTCOME MEASURES: Primary outcomes measured for each subject were LOS and total cost of treatment. RESULTS: The hospital admission rate for ADP vs control patients was 45.2% vs 100% (P<.001). The mean total cost per patient for ADP vs control patients was $1528 vs $2095 (P<.001). The mean LOS measured in hours for ADP vs control patients was 33.1 hours vs 44.8 hours (P<.01). CONCLUSIONS: In this trial, ADP saved $567 in total hospital costs per patient treated. Use of ED-based ADPs can reduce hospitalization rates, LOS, and total cost for low-risk patients with chest pain needing evaluation for possible AMI or ACI.

A comparison between emergency diagnostic and treatment unit and inpatient care in the management of acute asthma.

BACKGROUND: Emergency diagnostic and treatment units (EDTUs) may provide an alternative to hospitalization for patients with reversible diseases, such as asthma, who fail to adequately respond to emergency department therapy. OBJECTIVE: To evaluate the medical and cost-effectiveness, patient satisfaction, and quality of life of patients receiving EDTU care for acute asthma compared with inpatient care. METHODS: A prospective, randomized clinical trial performed at 2 urban public hospitals enrolled patients with acute asthma (age range, 18-55 years) not meeting discharge criteria after 3 hours of emergency department therapy. Patients were treated with inhaled adrenergic agonists and steroids in an EDTU for up to 9 hours after randomization or with routine therapy in a hospital ward. Patients were followed up for 8 weeks. MAIN OUTCOME MEASURES: Discharge rate from the EDTU, length of stay, relapse rates, days missed from work or school, days incapacitated during waking hours, symptom-free days and nights, nocturnal awakenings, direct medical costs, patients satisfaction, and patient quality of life. RESULTS: The study consisted of 222 patients with asthma. Sixty-five patients (59%) treated in an EDTU were discharged home; the remainder were admitted to the hospital. There were no differences during the follow-up period in relapse rates (P = .74) or in any other morbidities between the EDTU and inpatient groups. There were significant differences in the length of stay, patient satisfaction, and quality of life favoring EDTU care. The mean (+/-SD) cost per patient in the EDTU group was $1202.79 +/- $1343.96, compared with $2247.32 +/- $1110.18 for the control group (P < .001). CONCLUSIONS: Treatment of selected patients with asthma in an EDTU results in the safe discharge of most such patients. This study suggests that quality gains and cost-effective measures can be achieved by the use of such units.

A method of determining peritoneal penetration in gunshot wounds to the abdomen.

BACKGROUND: It has previously been shown that 98% of gunshot wounds that penetrate the peritoneal cavity cause injuries that require surgical repair. Many gunshot wounds in the vicinity of the abdomen (GSWA) may actually be tangential and not penetrate the peritoneal cavity at all. Patients with such wounds may not require laparotomy. It is important to determine which patients with a potential tangential GSWA actually have penetration of the peritoneal cavity to minimize negative laparotomies. This study was undertaken to determine the sensitivity, specificity, and accuracy of diagnostic peritoneal lavage (DPL) in the determination of peritoneal penetration for patients who sustain GSWA. METHODS: DPL was performed for all patients who had sustained a GSWA in whom peritoneal penetration was unclear, i.e., patients whose GSWA appeared to be tangential, thoracoabdominal, or transpelvic and for whom a clear indication for laparotomy (shock, peritonitis, etc.) did not exist. Our threshold for a positive DPL was 10,000 red blood cells (RBC)/mm3. A prospective data base was kept with information on the location of the wound, DPL result, findings at laparotomy, and outcome. RESULTS: During a 4-year period, 429 consecutive DPLs were performed for GSWA at our urban Level I trauma center. One hundred fifty DPLs were positive, with more than 10,000 RBC/mm3. Six of these patients were found to have no peritoneal penetration at laparotomy (false-positive). The remaining 144 patients with positive DPLs were found to have operative injuries (true-positive). Of the 279 patients with DPL counts less than 10,000 RBC/mm3, 2 developed indications for laparotomy and were found to have intraperitoneal injuries (false-negative). The remaining 277 patients had no peritoneal injuries (true-negative). This was demonstrated either by laparotomy done for another indication (n = 7) or by uneventful inpatient observation for 24 hours (n = 270). The sensitivity, specificity, and accuracy of DPL in determining peritoneal penetration in GSWA is therefore 99, 98, and 98%, respectively. CONCLUSION: For patients who sustain GSWA for whom peritoneal penetration is unclear, DPL is a sensitive, specific, and accurate test to determine the need for laparotomy. It remains our test of choice when confronted with these patients.

Feasibility of a rapid diagnostic protocol for an emergency department chest pain unit.

STUDY OBJECTIVE: To evaluate the applicability of a short-stay protocol for exclusion of acute ischemic heart disease without hospital admission and to analyze these results in the context of a conceptual model. METHODS: An observational study of patients who presented with chest pain to the emergency department of an 886-bed inner-city municipal hospital and who needed hospital admission to rule out acute myocardial infarction (AMI). Patients were assessed by ED attending physicians to determine eligibility for an alternative, 12-hour protocol in an ED chest pain observation unit (CPOU) followed by immediate exercise testing. Outcome measures were proportion of patients eligible for the short-stay protocol, risk factor profile, and reasons for exclusion. RESULTS: Of 500 patients screened, 446 had sufficient data points to determine protocol eligibility. Of these, 238 (53.3%; 95% confidence interval [CI], 48.7% to 57.9%) were found to have low probability for AMI. After study exclusion criteria were applied to the patient cohort, 63 patients (14.1%; 95% CI, 10.9% to 17.3%) were eligible for the protocol. The most common reasons for exclusion were history of coronary artery disease (46%) and inability to perform an interpretable exercise tolerance test (42%). CONCLUSION: Although most admitted patients with chest pain (53%) were at low probability for AMI, only a minority (14%) were eligible for a short-stay protocol that required patients to be free of known coronary artery disease and able to perform an exercise tolerance test. Factors affecting the operations and efficiency of a CPOU include clinical characteristics of the target patient population, protocol tests used, and hospital occupancy and reimbursement patterns.

Patient satisfaction with an emergency department chest pain observation unit.

STUDY OBJECTIVE: Patient satisfaction is an essential outcome measure in the diagnosis and treatment of acute chest pain in the emergency department. We compared patient satisfaction with the diagnostic protocol of a chest pain observation unit (CPOU) and standard inpatient hospitalization. METHODS: We prospectively studied patients who presented to the ED with chest pain and were found to have a low risk of acute myocardial infarction (AMI) but who still might have benefited from a diagnostic protocol to rule out AMI. Consenting patients (N = 104) were randomized to the CPOU (experimental) arm or the hospital inpatient (control) arm and assessed for satisfaction by means of an interview before hospital discharge. RESULTS: The CPOU protocol scored higher on four summary ratings of overall patient satisfaction. Correlations between overall satisfaction, number, and type of problems with care, and patient characteristics demonstrated content validity and revealed strengths and improvements that might be made in CPOUs. CONCLUSION: Patients were more satisfied with rapid diagnosis in the CPOU than with inpatient stays for acute chest pain. Our findings add important information to the standard practice of weighing clinical and cost outcomes between two medical care alternatives.