Associations between asthma trigger reports, mental health conditions, and asthma morbidity among world trade center rescue and recovery workers.

Aim: There is limited information regarding asthma triggers in World Trade Center (WTC) rescue and recovery workers (RRW) or how mental health conditions affect the perception of triggers. Methods: We included 372 WTC workers with asthma. The Asthma Trigger Inventory (ATI) assessed triggers along five domains: psychological, allergens, physical activity, infection, and pollution. We administered the Structured Clinical Interview to diagnose post-traumatic stress disorder (PTSD), major depression and panic disorder (PD). The Asthma Control Questionnaire (ACQ) and Mini Asthma Quality of Life Questionnaire (AQLQ) measured asthma control and quality of life, respectively. Linear regression models were fitted to examine the association of ATI total and subdomain scores with mental health conditions as well as the percent of ACQ and AQLQ variance explained by ATI subscales. Results: The most common triggers were air pollution (75%) and general allergens (68%). PTSD was significantly associated with psychological triggers (partial r2=0.05, p < 0.01), physical activity (partial r2=0.03, p < 0.01) and air pollution (partial r2=0.02, p = 0.04) subscales while PD was significantly associated with air pollution (partial r2=0.03, p = 0.03) and general allergens (partial r2=0.02, p = 0.03). ATI subscales explained a large percentage of variance in asthma control (r2=0.37, p < 0.01) and quality of life scores (r2=0.40, p < 0.01). Psychological subscale scores explained the largest portion of the total variability in ACQ (partial r2= 0.11, p = 0.72) and AQLQ (partial r2=0.14, p = 0.64) scores. Conclusion: RRW with mental health conditions reported more asthma triggers and these triggers were associated with asthma morbidity. These data can help support interventions in RRW with asthma.

Gastrointestinal carcinoids: characterization by site of origin and hormone production.

OBJECTIVE: To describe a large series of patients with carcinoid tumors in terms of presenting symptoms, hormonal data, stage at diagnosis, pathologic features, and survival. SUMMARY BACKGROUND DATA: Published series have described significant prognostic features of carcinoid tumors as site of origin, age, sex, stage at diagnosis, presence of high hormone levels, and increased T stage. Of these, stage at diagnosis and T stage seem to emerge most often as independent predictors of survival in multivariate analyses. Of carcinoid tumors, those arising from a midgut location have higher levels of serotonin and serotonin breakdown products, as well as more frequent metastatic disease at presentation, than those arising from either foregut or hindgut locations. METHODS: A prospective database of carcinoid patients seen at Duke University Medical Center was kept from 1970 to the present. Retrospective medical record review was performed on this database to record presenting symptoms, hormonal data, pathologic features, and survival. Statistical methods included analysis of variance, Kaplan-Meier analysis, and Mantel-Cox proportional hazard survival analysis, with P <.05 considered significant for all tests. RESULTS: Carcinoids arising in different locations had different presentations: rectal carcinoids presented significantly more often with gastrointestinal bleeding, and midgut carcinoids presented significantly more often with flushing, diarrhea, and the carcinoid syndrome. Patients with midgut tumors had significantly higher levels of serotonin and serotonin breakdown products, corresponding to higher metastatic tumor burdens. Although age, stage, region of origin, and urinary level of 5-hydroxyindoleacetic acid predicted survival by univariate analysis, only the latter three were independent predictors of survival by multivariate analysis. Of the patients with metastatic disease at diagnosis, those with midgut tumors had better survival than those with foregut or hindgut tumors. CONCLUSIONS: Although region of origin is certainly an important factor in determination of prognosis, stage of disease at presentation is more predictive of survival. Pancreatic and midgut carcinoids are metastatic at diagnosis more often than those arising in other locations, leading to a worse overall prognosis. Among patients with distant metastases, patients with midgut primary tumors have improved survival despite increased hormone production compared with patients with tumors arising in other primary sites.

Foregut carcinoids: a clinical and biochemical analysis.

BACKGROUND: Gastrointestinal foregut carcinoids make up a small percentage (3% to 6%) of all reported carcinoids. Because these tumors are so uncommon, comparisons between the subtypes have been difficult. The goal of this study was to compare the hormonal and clinical characteristics of gastric, duodenal, and pancreatic carcinoids. METHODS: A prospective database of approximately 750 carcinoid patients seen by one author over 25 years was reviewed, and the 104 patients with gastric (33), duodenal (17), or pancreatic (54) carcinoids were selected as the subgroup for analysis. These patients were compared with regard to hormone levels, clinical course, treatment, and survival. RESULTS: Duodenal carcinoids exhibited significantly lower serotoninergic hormone levels than did the gastric and pancreatic carcinoids (urine 5-hydroxyindoleacetic acid [mg/24 h], 5 +/- 1 vs 16 +/- 5 and 47 +/- 12, respectively, P = .03). Pancreatic carcinoids presented with more advanced stage (distant metastases 87% vs 42% and 20% for gastric and duodenal, respectively) and had worse outcomes than patients with gastric and duodenal tumors with 10-year survivals of 10%, 59%, and 58%, respectively (P = .003). CONCLUSIONS: Pancreatic carcinoids produce higher levels of serotoninergic hormones and have a significantly higher stage and worse outcome than other foregut carcinoids. This study demonstrates that the organ of origin is an important determinant of hormonal activity and clinical course for patients with foregut carcinoids.

A simple strategy for faster induction and more cost-effective use of anesthetic vapor.

INTRODUCTION: Inducing general anesthesia often involves mask ventilation using high fresh gas flow (FGF) to administer anesthetic vapor prior to endotracheal intubation. A common practice is to turn the vaporizer off when the mask is removed from the patient's face to avoid room contamination (VAPOff). An alternative approach is to leave the vaporizer on and turn the FGF to minimum to reduce the amount of vapor laden gas that can enter the room (FGFOff). The objective of this study is to compare the relative induction times and vapor costs associated with each induction strategy. METHODS: Each induction method was simulated using Gasman (MedMan Simulations, Chestnut Hill, MA) for Windows assuming a 70 kg patient. To simulate a period of mask ventilation with anesthetic vapor prior to intubation, the FGF was set to 6 l/min and the isoflurane vapor concentration to 1.2% (1 MAC) for three minutes with an alveolar ventilation of 5 l/min and cardiac output of 5 l/min. For the first simulation of the intubation period (FGFOff), FGF was turned to 150 ml/min, minute ventilation was set to zero and the vaporizer setting unchanged for one minute. Initial settings were then restored and the rate of change of anesthetic vapor concentration in the circuit (Vckt) and alveolus (Valv) followed for 10 minutes along with the cost of delivered vapor (V(S)). For the second simulation (VAPOff), after the initial three minutes of vapor delivery, the vaporizer was set to zero, minute ventilation was set to zero and the FGF left unchanged for one minute. The initial settings were then restored and Vckt, Valv and V(S) followed for ten minutes. The cost calculation was based upon a 100 ml bottle of Isoflurane at $72/bottle. Actual gas flow was measured at the y-piece of a circle system for fresh gas flows from 0.15 to 6 l/min. RESULTS: At the end of the simulated intubation period (minute 4), Vckt was unchanged with the FGFOff method whereas it had fallen by more than half with the VAPOff method. Using VAPOff, it took until the 6-minute mark for Vckt to return to the same concentration that existed prior to intubation at minute three. Throughout the 10 minute simulated induction, Valv using FGFOff exceeded Valv using VAPOff although the difference became small at the end of the period. V(S) was essentially identical at all time points. No flow into the room was measured at the minimum fresh gas flow whereas higher fresh gas flows resulted in a significant portion of the fresh gas flowing into the, room. CONCLUSIONS: The strategy of turning the FGF to minimum and leaving the vaporizer on during intubation does not contaminate the room and speeds induction by fostering a greater alveolar concentration than the VAPOff method. Cost savings are derived using FGFOff since a higher alveolar concentration is achieved at the same vapor cost. Additional cost savings are demonstrated since a low flow technique is possible immediately after intubation when using FGFOff. The practice of turning off the vaporizer during endotracheal intubation while FGF remains high should be abandoned.

Carcinoids of unknown origin: comparative analysis with foregut, midgut, and hindgut carcinoids.

BACKGROUND: Carcinoids are rare neuroendocrine tumors typically arising in the gastrointestinal tract. A significant percentage of these tumors present as metastatic disease of unknown primary site. The aim of this study was to better define the functional and clinical characteristics of carcinoids of unknown primary (CUP) site. METHODS: This study examines the hormonal activity, clinical characteristics, and survival of 434 patients with carcinoids originating in the foregut, midgut, hindgut, or unknown location. The 143 patients with CUP were compared with the other groups with regard to presenting characteristics, diagnostic tests and therapeutic modalities used, hormonal activity, and survival. RESULTS: The hormone levels (urinary 5-hydroxyindoleacetic acid and serotonin, serum and platelet serotonin) of CUP were not significantly different from midgut carcinoids with metastatic disease. Although survival with CUP was shorter than with carcinoids with identified primaries (10-year survivals of 22% vs 62%, 50%, and 48% for foregut, midgut, and hindgut, respectively), the survival curve for CUP was quite similar to that of patients with midgut carcinoids with distant disease (10-year survival of 22% vs 28%). CONCLUSIONS: CUP are similar to midgut carcinoids presenting with metastatic disease with regard to hormone production and survival. Like other carcinoids, CUP can be an indolent disease process with gradual progression over decades.

Iodine-131-metaiodobenzylguanidine uptake in metastatic carcinoid tumor to the orbit.

Metastatic tumor is one of several etiologies of space-occupying masses in the orbit that accounts for 1%-13% of all orbital masses (1). In the adult patient population, breast cancer is the most common tumor to metastasize to the orbit followed by metastases from the lung, prostate and gastrointestinal tract (2). It is rare for carcinoid tumors to metastasize to the eye or to the orbit. Carcinoid tumors arise from Kulchitsky cells that originate in the neural crest. Histologically, these tumors resemble, but are not as aggressive as, adenocarcinomas. Most carcinoids arise in the gastrointestinal tract or the lung. The most common site for carcinoid metastases is the liver. On anatomical imaging studies, such as CT and magnetic resonance imaging, metastatic orbital carcinoid tumors appear as nonspecific tumor masses. Carcinoid tumors have an affinity for uptake of the radiopharmaceutical 131I-metaiodobenzylguanidine (MIBG) (3). We report a case of a patient with a known carcinoid tumor who developed a left orbital mass that demonstrated abnormal uptake of 131I-MIBG indicative of metastatic carcinoid tumor to the orbit.

Ileal carcinoid tumors stimulating Crohn's disease: incidence among 176 consecutive cases of ileal carcinoid.

OBJECTIVE: There are seven published cases of ileal carcinoid tumor misdiagnosed and treated as Crohn's disease. We evaluated 176 consecutive ileal carcinoid patients to determine the frequency with which this occurs. Clinical, hormonal, and radiographic data of those patients misdiagnosed were also analyzed to determine whether there were clinical lessons to be learned. METHODS: Records of 176 patients with ileal carcinoid tumors were retrospectively reviewed. It was determined whether patients were diagnosed and treated for Crohn's before the diagnosis of carcinoid was established. Radiographic, hormonal, and clinical data were reviewed and comparison was made to those who were correctly diagnosed as having carcinoid. RESULTS: Of 176 ileal carcinoid patients, 4 were initially diagnosed and treated as having Crohn's; their mean age was 51.5 +/- 8.9 yr. The hormonal data of patients treated as Crohn's was indistinguishable from patients with known carcinoid. Two of four patients had colonoscopy performed, neither had terminal ileal intubation. None responded to medical therapy and all required surgery for diagnosis. The mean time from symptom onset to the establishment of the correct diagnosis was 24 +/- 6.9 months with a range of 6 to 45 months. CONCLUSIONS: Although rare, ileal carcinoid tumors may be misdiagnosed as Crohn's disease. In our study approximately 2.3% of patients with ileal carcinoid were initially diagnosed and treated as having Crohn's disease. The presence of disease refractory to medical therapy should alert clinicians to this possibility and urinary 5-HIAA levels should be obtained as a screening test.

A robust sensor fusion method for heart rate estimation.

PROBLEM: Physiologic data measured in the clinical environment is frequently corrupted causing erroneous data to be displayed, periods of missing information or nuisance alarms to be triggered. To date, the possibility of combining sensors with similar information to improve the quality of the extracted data has not been developed. The objective of this work is to develop a method for combining heart rate measurements from multiple sensors to obtain: (i) an estimate of heart rate that is free of artifact; (ii) a confidence value associated with every heart rate estimate which indicates the likelihood that an estimate is correct; (iii) a more accurate estimate of heart rate than is available from any individual sensor. SOLUTION: The essence of the method is to discriminate between good and bad sensor measurements and combine only the good readings to derive an optimal heart rate estimate. Past estimates of heart rate are used to derive a predicted value for the current heart rate that is also fused along with the sensor measurements. Consensus between sensor measurements, the predicted value and physiologic credibility of the readings are used to distinguish between good and bad readings. Three sensor measurements and the predicted value are evaluated yielding 16 possible hypotheses for the current state of the available data. A Kalman filter uses the most likely hypothesis to derive the fused estimate. Statistical measures of the sensor error and rate of change of heart rate are adaptively estimated when data are sufficiently reliable and used to enhance the hypothesis selection process. DISCUSSION: The method of sensor fusion presented has been documented to perform well using clinical data. Limitations of the technique and the assumptions employed are discussed as well as directions for future research.

Robust sensor fusion improves heart rate estimation: clinical evaluation.

OBJECTIVE: To determine if Robust Sensor Fusion (RSF), a method designed to fuse data from multiple sensors with redundant heart rate information can be used to improve the quality of heart rate data. To determine if the improved estimate of heart rate can reduce the number of false and missed heart rate alarms. METHODS: A total of 85 monitoring periods were investigated, 12 from the operating room, 60 from adult ICU and 13 from pediatric ICU. The operating room periods began with induction of anesthesia and ended at the completion of the anesthetic. For the ICU data, four hour blocks of time were studied. For each monitoring period, HR values were recorded at 5 second intervals or less from the ECG, SpO2 and IAC using a SpaceLabs Medical Gateway connected to a SpaceLabs Medical PC2. Fused estimates of HR were derived for every time point using RSF and all results accepted regardless of confidence value. Data were annotated manually to identify the "reference" HR (that HR value most likely to be correct) at all time points. All HR values from the sensors and the fused estimate that were different from the reference HR by more than +/- 5 beats/min were considered inaccurate. For each monitoring period, the total time per hour that data were either inaccurate or unavailable was calculated for each sensor as well as the fused estimates. The total time of false and missed HR alarms was found for all sensors and the fused estimate by comparing the data to thresholds for both high and low HR alarms at 150 bpm, 130 bpm, 110 bpm and 50 bpm, 40 bpm, 30 bpm respectively. RESULTS: The fused estimate of HR was consistently as good or better than the estimate available from any individual sensor. The fused estimates also consistently reduced the incidence of false alarms compared with individual sensors without an unacceptable incidence of missed alarms. DISCUSSION: Redundancy in sensor measurements can be used to improve HR estimation in the clinical setting. Methods like RSF which improve the quality of monitored data and reduce nuisance alarms will enhance the value of patient monitors to clinicians.

Pupillary dilation and funduscopy with 1.0% hydroxyamphetamine plus 0.25% tropicamide (Paremyd) versus tropicamide (0.5 or 1.0%) as a function of iris and skin pigmentation, and age.

BACKGROUND: This study was designed to evaluate the effect of Paremyd, a combination of 1.0 percent hydroxyamphetamine hydrobromide and 0.25 percent tropicamide, on pupil size during binocular indirect ophthalmoscopy (BIO) upon 164 subjects of various skin pigmentation, iris color, and age. METHODS: Pupillary dilation and ease of performing BIO were measured after 30 minutes following instillation of a single drop of either Paremyd or tropicamide (1.0 or 0.5 percent) to an eye. Subjects were assigned to one of three groups; either Paremyd OU, or Paremyd OS and tropicamide (either 0.5 or 1.0 percent) OD, or Paremyd OD and tropicamide OS. Pupillary dilation was measured during BIO performed at a set illumination using a near point card. RESULTS: Results indicate that Paremyd is a significantly more effective dilator than either concentration of tropicamide alone. BIO was rated good to excellent for all dilating agents. As could be expected (based upon data from previous experiments), there was a small, but significant, negative correlation between dilation and age, skin pigmentation, and iris pigmentation. CONCLUSIONS: Paremyd, because of its superior effect upon dilation without side effects, can be the preferred agent used for routine single-drop dilation in all patients, independent of age, iris color, or skin color.

Carcinoid of the ampulla of Vater presenting as acute pancreatitis.

A 30-yr-old female with a carcinoid tumor of the ampulla of Vater is discussed. This rare tumor presented in an unusual fashion with isolated pancreatitis in the absence of cholestasis. The correct diagnosis was made preoperatively by endoscopic retrograde cholangiography with biopsies. Surgical removal led to complete resolution of symptoms. The importance of considering less common structural lesions such as ampullary carcinoids in the differential diagnosis of pancreatitis in patients without identifiable risk factors is stressed.

Carcinoid heart disease. Correlation of high serotonin levels with valvular abnormalities detected by cardiac catheterization and echocardiography.

BACKGROUND: Although serotonin has been postulated as an etiologic agent in the development of carcinoid heart disease, no direct evidence for different ambient serotonin levels in cardiac and noncardiac patients has been reported to date. METHODS AND RESULTS: The present study reviews our experience with 604 patients in the Duke Carcinoid Database. Nineteen patients with proven carcinoid heart disease (by cardiac catheterization and/or echocardiogram) were compared with the remaining 585 noncardiac patients in the database with regard to circulating serotonin and its principal metabolite, 5-hydroxyindole acetic acid (5-HIAA). No significant demographic differences existed between the cardiac and noncardiac groups; however, typical carcinoid syndrome symptoms (ie, flushing and diarrhea) were almost threefold more common in the cardiac group (P < .001). Compared with the noncardiac group, heart disease patients demonstrated strikingly higher (P < .0001) mean serum serotonin (9750 versus 4350 pmol/mL), plasma serotonin (1130 versus 426 pmol/mL), platelet serotonin (6240 versus 2700 pmol/mg protein), and urine 5-HIAA (219 versus 55.3 mg/24 h) levels. The spectrum of heart disease among the 19 patients showed a strong right-sided valvular predominance, with tricuspid regurgitation being the most common valvular dysfunction (92% by cardiac catheterization; 100% by echocardiogram). CONCLUSIONS: These data suggest that serotonin plays a major role in the pathogenesis of the cardiac plaque formation observed in carcinoid patients.

Midgut carcinoid tumors: CT findings and biochemical profiles.

OBJECTIVE: Our goal was to describe the abdominal CT findings in 52 patients with midgut carcinoid tumors and correlate these findings with their biochemical profiles. MATERIALS AND METHODS: Abdominal/pelvic CTs of 52 patients with midgut carcinoid tumors were reviewed retrospectively for the presence of liver metastases, mesenteric and peritoneal disease, bowel changes, lymphadenopathy, and the presence of the primary tumor. Logistic regression models were used to evaluate the association between these findings and the serum and platelet serotonin and urine 5-hydroxyindolacetic acid levels. RESULTS: The most common finding was hepatic metastases (34/52). Nonspecific mesenteric soft tissue stranding was present in 26 of 52 and a discrete mesenteric mass was present in 25 of 52. These masses had linear, radiating soft tissue spokes in 16 of 25 and contained calcification in 10 of 25. Retroperitoneal and mesenteric lymphadenopathy was present in 14 of 52 and 11 of 52 cases, respectively. Carcinomatosis was present in 11 of 52. Bowel wall thickening was seen in 9 of 52. Six patients had a small bowel obstruction. Elevated serum serotonin, platelet serotonin, and urine 5-hydroxyindolacetic acid levels were significantly associated with the presence of liver metastases (p = 0.0032, 0.0098, and 0.0450, respectively). Elevated platelet serotonin levels were also significantly associated with the presence of a mesenteric mass (p = 0.0101). CONCLUSION: In our population, the most common findings of a midgut carcinoid tumor are liver metastases, nonspecific mesenteric soft tissue changes, a discrete mesenteric mass with radiating soft tissue spokes, often containing calcification, and lymphadenopathy. As expected, liver metastases correlate strongly with the presence of elevated biochemical levels. A new observation is the correlation of elevated platelet serotonin levels and mesenteric masses. We hypothesize that platelet serotonin may be the factor that stimulates stromal cells to produce mesenteric fibrosis and mass formation.

Predictors of outcome of tricuspid valve replacement in carcinoid heart disease.

The cardiac valvular surgical experience of patients in the Duke Carcinoid Database was reviewed to assess operative outcome. Of the 604 patients in the database, 19 patients with carcinoid heart disease were identified by cardiac catheterization or echocardiography, or both. Eight of these underwent tricuspid valve replacement surgery with bioprostheses (2 also had open pulmonic valvuloplasty). Compared with patients medically managed, surgically treated patients were similar with the exception that they had higher right atrial mean (17 +/- 6 vs 9 +/- 4 mm Hg, p = 0.03) and v-wave (27 +/- 6 vs 17 +/- 7 mm Hg, p = 0.04) pressures. Of the 8 surgical patients, 5 (63%) died within 30 days. Causes of death included tricuspid valve thrombosis, cerebral vascular accident, coagulopathy, renal failure, and intractable right heart failure. High comorbidity was present in all 8 patients. There was a weak trend (p = 0.17) toward lower Charlson comorbidity indexes in survivors (6.7 +/- 0.6) compared with nonsurvivors (7.6 +/- 0.9). Age was significantly lower (p = 0.036) in survivors (46 +/- 13 years) compared with nonsurvivors (69 +/- 4 years). Extended follow-up revealed 2 patients who survived beyond a decade. Review of 47 carcinoid valve replacement cases (Duke Carcinoid Database and 39 published cases) revealed a 30-day mortality of 56% for patients > 60 years of age, and 0% for those < or = 60 years of age (p < 0.0001). Although valve replacement surgery can afford prolonged palliation from carcinoid heart disease, it is associated with a significant mortality risk. Careful preoperative risk stratification by age and comorbidity may provide a means for optimal selection of surgical candidates.

Diagnostic and therapeutic considerations in a hypercalcemic dog with multiple endocrine neoplasia.

Hypercalcemia was found in a dog examined for episodic weakness and disorientation. A right adrenal mass identified on abdominal ultrasonographic examination was diagnosed as a pheochromocytoma based on increased 1231-metaiodobenzylguanidine uptake and characteristic histopathological features. Serum intact parathyroid hormone (iPTH), total serum calcium, and ionized serum calcium were increased prior to surgery. Although both total and ionized serum calcium concentrations decreased to within normal reference ranges following surgery through postoperative day 17, subsequent high concentrations with increased serum iPTH concentrations confirmed concurrent primary hyperparathyroidism. A right parathyroid tumor was suspected based on a technetium-99m-sestamibi (99mTc-sestamibi) scan.

Tangled in the web: countertransference in the therapy of factitious disorders.

OBJECTIVE: Patients who simulate or actually self-induce illnesses to assume the "sick role" present a number of imposing psychotherapeutic challenges. The purpose of this article is to discuss the countertransferential reactions that are mobilized in therapy with these patients. METHODS: Literature searches of the MEDLINE and HEALTH databases were performed using the term "factitious disorder." The resulting citations were examined for descriptions of the potential and actual countertransference responses in therapy with such patients. The few citations with relevant material were supplemented with other clinical literature on countertransference as well as observations from cases in which the authors have served as therapists or consultants. RESULTS: Once the medical dissimulation has been exposed, the most conspicuous difficulty is in persuading the patient to agree to therapy. When therapy does take place, both the patient's overt behaviors, such as actual bodily damage, and his or her underlying emotional issues can mobilize particularly intense reactions in the therapist. CONCLUSIONS: Recognition and management of the countertransference reactions likely to emerge in therapy with factitious disorder patients are particularly important if the therapy is to be maximally effective.

Maximum blood savings by acute normovolemic hemodilution.

Acute normovolemic hemodilution (ANH) entails collecting blood from a patient immediately prior to surgery with concurrent fluid infusion to maintain intravascular volume constant. Blood collected during ANH is later reinfused to replace the red cell losses that occur during surgery. This technique is advocated as a means to reduce or eliminate homologous blood transfusion during surgery. Published guidelines for performing ANH vary, and the literature does not describe how to perform ANH to achieve the maximum benefit for a given patient. To evaluate how to save red blood cells as much as possible via ANH, and to determine the maximum benefit that can be expected, we developed a mathematic model of the process. Using the model, the net red cell mass savings possible when using ANH can be calculated given the patient's weight, initial hematocrit and minimum safe hematocrit. Results are reported to demonstrate the impact of the initial hematocrit and minimum safe hematocrit on the red cell savings possible with ANH. The data indicate that ANH does indeed save red blood cells that would otherwise be lost during surgery. However, the red cell savings possible when using ANH are not as much as typically published and, a degree of hemodilution more than that which is typically recommended is necessary to achieve even modest red cell savings.

Do agents used for epidural analgesia have antimicrobial properties?

BACKGROUND AND OBJECTIVES: Local anesthetics inhibit bacteria growth in culture although this effect diminishes as the concentration of the drug is reduced. The antimicrobial properties of opioids are unknown. This study was designed to determine the ability of lidocaine and bupivacaine, with or without fentanyl or sufentanil, to inhibit bacteria growth in culture at concentrations typically used to provide analgesia. METHODS: Potential bacteria pathogens were cultured in agar media containing: agar alone, 2%, 1.5%, and 1% lidocaine, 0.5%, 0.25%, and 0.125% bupivacaine, 0.125% bupivacaine + fentanyl 2 mcgs/mL, 0.125% bupivacaine + sufentanil 0.3 mcgs/mL, and fentanyl 5 mcgs/mL, fentanyl 2 mcgs/mL or sufentanil 0.3 mcgs/mL. Organisms were deemed sensitive to the study agent if no growth was apparent after incubation for 24 hours. RESULTS: Both lidocaine and bupivacaine significantly reduced bacteria growth at all concentrations studied compared to the growth observed in agar alone (P < .0001). This growth inhibition diminished as the concentration of local anesthetic was reduced especially for certain bacteria species for example. Staphylococcus aureus (P < .0001). Neither fentanyl nor sufentanil inhibited any bacterial growth in culture. CONCLUSIONS: Since the growth in culture of common pathogens, especially S. aureus, is not inhibited as the concentration of local anesthetic is reduced, the local anesthetics tested are unlikely to help prevent epidural-catheter-related infection due to common pathogens. More study is necessary to determine if local anesthetics help prevent infection from less common pathogens in patients at increased risk for infectious complications.