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Biomedical subjects

P L Havens

Publications and source records attributed to P L Havens.

At least 19 recordsLinked to original sources

Detection of Pseudomonas aeruginosa type III antibodies in children with tracheostomies.

Pseudomonas aeruginosa is often cultured from the airways of children with tracheostomies. P. aeruginosa produces exotoxin A (ETA) and type III cytotoxins. This study tested the hypothesis that children with tracheostomies are colonized by P. aeruginosa that express these virulence factors and will have antibodies directed against these virulence factors, indicating infection rather than only colonization. A convenience sample of 30 patients, ranging in age from 2 months-22 years, was recruited. Serum was tested for the presence of antibodies to ETA and components of the type III system by Western blot analysis. Twenty-one of 39 patients (70%) had antibodies to components of the type III system. Fifteen of 30 (50%) were seropositive for ETA. Sera from patients who were antibody-positive for ETA were also seropositive for either ExoS or ExoU. Nine of 30 patients (30%) did not possess antibodies to ETA or components of the type III system. In conclusion, these data identified a seropositive reaction to P. aeruginosa cytotoxins in some patients with tracheostomies, suggestive of infection by cytotoxic strains of P. aeruginosa. Future studies will determine the utility of measuring seroconversion to these cytotoxins as an early indication of infection in children with tracheostomies.

ADP Ribose Transferases↗

Unmeasured anions identified by the Fencl-Stewart method predict mortality better than base excess, anion gap, and lactate in patients in the pediatric intensive care unit.

OBJECTIVES: This study was undertaken to compare three methods for the identification of unmeasured anions in pediatric patients with critical illness. We compared the base excess (BE) and anion gap (AG) methods with the less commonly used Fencl-Stewart strong ion method of calculating BE caused by unmeasured anions (BEua). We measured the relationship of unmeasured anions identified by the three methods to serum lactate concentrations and to mortality. DESIGN: Retrospective cohort study. SETTING: Tertiary care pediatric intensive care unit in an academic pediatric hospital. PATIENTS: The study population included 255 patients in the pediatric intensive care unit who had simultaneous measurements of arterial blood gases, electrolytes, and albumin during the period of July 1995 to December 1996. Sixty-six of the 255 patients had a simultaneous measurement of serum lactate. MEASUREMENTS AND MAIN RESULTS: The BEua was calculated using the Fencl-Stewart method. The AG was defined as (sodium plus potassium) - (chloride plus total carbon dioxide). BE was calculated from the standard bicarbonate, which is derived from the Henderson-Hasselbalch equation and reported on the blood gas analysis. A BE or BEua value of < or =-5 mEq/L or an AG > or =17 mEq/L was defined as a clinically significant presence of unmeasured anions. A lactate level of > or =45 mg/dL was defined as being abnormally elevated for this study. The presence of unmeasured anions identified by significantly abnormal BEua was poorly identified by BE or AG. Of the 255 patients included in the study, 67 (26%) had a different interpretation of acid base balance when the Fencl method was used compared with when BE and AG were used. Plasma lactate concentration correlated better with BEua (r2 = .55; p = .0001) than with AG (r2 = .41; p = .0005) or BE (r2 = .27; p = .025). Mortality was more strongly related to BEua < or =-5 mEq/L (relative risk of death = 10.25; p = .002) than to lactate > or =45 mg/dL (relative risk of death = 2.35; p = .04). In logistic regression analysis, mortality was more strongly associated with BEua (area under the receiver operating characteristic curve = 0.79; p = .0002) than lactate (receiver operating characteristic curve area = 0.63; p = .05), BE (receiver operating characteristic curve area = 0.53; p = .32), or AG (receiver operating characteristic curve area = 0.64; p = .08) in this patient sample. CONCLUSIONS: Critically ill patients with normal BE and normal AG frequently have elevated unmeasured anions detectable by BEua. The Fencl-Stewart method is better than BE and similar to AG in identifying patients with high lactate levels. Elevated unmeasured anions identified by the Fencl-Stewart method were more strongly associated with mortality than with BE, AG, or lactate in this patient sample.

Acid-Base Equilibrium↗

Cryptosporidiosis in children during a massive waterborne outbreak in Milwaukee, Wisconsin: clinical, laboratory and epidemiologic findings.

During the spring of 1993 an estimated 403000 residents of the greater Milwaukee, Wisconsin area experienced gastrointestinal illness due to infection with the parasite Cryptosporidium parvum following contamination of the city's water supply. To define the clinical, laboratory and epidemiologic features of outbreak-associated cryptosporidiosis in children, medical and laboratory records for all children submitting stool samples to the microbiology laboratory of the Children's Hospital of Wisconsin between 7 April and 13 May 1993 were reviewed retrospectively. Interviews with parents were also conducted to obtain additional clinical history. Cryptosporidium, as the sole pathogen, was identified in stools from 49 (23%) of the 209 children enrolled in the study. Children with laboratory-confirmed cryptosporidiosis were more likely to live in areas of Milwaukee supplied with contaminated water (RR = 1.92, CI = 1.19-3.09), to be tested later in their illness (P < 0.05), to have submitted more than one stool specimen (P = 0.01), to have an underlying disease that altered their immune status (RR = 2.78, CI = 1.60-4.84), and to be older than 1 year of age (RR = 2.02, CI = 1.13-3.60). Clinical illness in these patients was more prolonged and associated with weight loss and abdominal cramps compared with Cryptosporidium-negative children. In the context of this massive waterborne outbreak relatively few children had documented infection with Cryptosporidium. If many children who tested negative for the parasite were truly infected, as the epidemiologic data suggest, existing laboratory tests for Cryptosporidium were insensitive, particularly early in the course of illness.

Adolescent↗

Measurements of total plasma nitrite and nitrate in pediatric patients with the systemic inflammatory response syndrome.

OBJECTIVES: The systemic inflammatory response syndrome (SIRS) is typified by the presence of fever, hemodynamic changes, and end organ dysfunction. Endothelial cell activation leads to overproduction of nitric oxide, which results in sustained vasodilation and hypotension. This study was undertaken to determine the sensitivity, specificity, and positive and negative predictive values of plasma nitrite/nitrate measurements in identifying patients with clinical characteristics of SIRS, as defined by criteria based on physician diagnosis. DESIGN: Prospective cohort study with consecutive sampling of patients. SETTING: Tertiary, multidisciplinary, pediatric intensive care unit (ICU) at Children's Hospital of Wisconsin. PATIENTS: Patients were divided into five groups. There were 16 pediatric controls undergoing elective surgery and 177 pediatric ICU patients without and 46 pediatric ICU patients with physician-diagnosed sepsis, septic shock, SIRS, or sepsis syndrome documented in the medical record (all considered physician-diagnosed sepsis). The 223 pediatric ICU patients included 195 pediatric ICU patients not meeting and 28 pediatric ICU patients meeting predetermined physiologic criteria for SIRS (considered criteria-based sepsis). INTERVENTIONS: Blood samples were obtained for quantitative nitrite/nitrate analysis at the time of admission to the pediatric ICU and daily until discharge. MEASUREMENTS AND MAIN RESULTS: Mean plasma nitrite/nitrate concentrations in the controls were 34.5 +/- 12 microM (95th percentile 54 microM). In pediatric ICU patients without and with physician-diagnosed sepsis, mean plasma nitrite/nitrate concentrations were 39 +/- 24 microM (p > .05 compared with controls) and 127 +/- 91 microM (p < .0001 compared with both controls and patients without physician-diagnosed sepsis), respectively. In pediatric ICU patients without and with criteria-based sepsis, the mean total plasma nitrite/nitrate concentrations were 56 +/- 59 microM (p = .008 compared with controls) and 80 +/- 64 microM (p = .003 compared with patients without criteria-based sepsis), respectively. The ability of plasma nitrite/nitrate > 54 microM to identify patients with physician-diagnosed sepsis is characterized as follows: 87% sensitivity, 77% specificity, 50% positive predictive value, and 96% negative predictive value. The ability of plasma nitrite/nitrate > 54 microM to identify patients with criteria-based sepsis is characterized as follows: 61% sensitivity, 68% specificity, 21% positive predictive value, and 92% negative predictive value. CONCLUSIONS: Clinical diagnosis of SIRS is strongly associated with increased total plasma nitrite/nitrate concentrations in pediatric patients in the pediatric ICU. Many patients with increased nitrite/nitrate concentrations have inflammation without having a clinical diagnosis of SIRS. Our data suggest that increased plasma nitrite/nitrate concentrations are the standard for identifying patients with inflammation in the pediatric ICU.

Child, Preschool↗

Survival and functional outcome of children requiring endotracheal intubation during therapy for severe traumatic brain injury.

OBJECTIVE: To determine the predictors of survival and functional outcome of pediatric patients with traumatic brain injury severe enough to require endotracheal intubation and mechanical ventilation. DESIGN: Retrospective, observational cohort study. SETTING: Pediatric intensive care unit (ICU) at a tertiary care children's hospital. PATIENTS: All children (n = 105) admitted over a 5-yr period with traumatic brain injury severe enough to require endotracheal intubation and mechanical ventilation. The median age was 43 months (range 1 month to 14 yrs). Of these children, 74% were male and 70% were white. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Variables studied included vital signs during the first 24 hrs of admission, Pediatric Risk of Mortality (PRISM) score, Glasgow Coma Score, duration of mechanical ventilation, and number of pediatric ICU and hospital days. Functional status was graded as normal, independent, partially dependent, or dependent in the areas of locomotion, self-care, and communication. This status was assessed at hospital discharge by chart review and at follow-up by telephone interview. The median Glasgow Coma Score was 6 (range 3 to 14) and the median PRISM score was 13 (range 1 to 51). There were 19 (18.1%) deaths, 17 in the pediatric ICU and two after hospital discharge. Of the patients who survived to hospital discharge, 39 (37.1%) patients were completely normal or independent, 42 (40%) patients were partially dependent, and seven (6.7%) patients were dependent in all three areas of function. Follow-up evaluations were available for 80 patients, with a median follow-up time of 24.5 months (range 8 to 70). Of the 78 patients who survived and were available for follow-up, the number who were functionally normal or independent increased to 69 (65.7%). At follow-up, there were eight (7.6%) patients remaining with partial dependency in at least one area of function while one (0.9%) patient continued to be dependent in all three areas of function. Mortality and dependent functional outcome were more likely in patients with younger age, lower Glasgow Coma Score, and higher PRISM score at hospital admission. Of the 27 patients with a Glasgow Coma Score of < or = 5, 11 (40.7%) survived with normal or independent functional status at follow-up. Of the 24 patients with PRISM scores of > 20, only five (20.8%) were functionally normal or independent at follow-up. The relative risk of a bad outcome for patients with a Glasgow Coma Score of < or = 5 and a PRISM score of > or = 20 was ten times higher than the group of patients with a Glasgow Coma Score of < or = 5 but a PRISM score of < 20. CONCLUSIONS: Children with severe traumatic brain injury who survive to hospital discharge will continue to improve in their functional status over the next few years. Although low Glasgow Coma Score is strongly associated with death or poor functional outcome after therapy for traumatic brain injury, many patients with Glasgow Coma Score of < or = 5 can survive with good function. PRISM scores add to the power of Glasgow Coma Score to predict survival and functional outcome in tracheally intubated pediatric patients with Glasgow Coma Score of < or = 5.

Activities of Daily Living↗

Structure of a primary care support system to coordinate comprehensive care for children and families infected/affected by human immunodeficiency virus in a managed care environment.

BACKGROUND: Children with HIV infection require coordinated primary and tertiary care. OBJECTIVES: To describe the structure of the Wisconsin HIV Primary Care Support Network, a decentralized program for care of children and families infected or affected by HIV infection. METHODS: Review of data concerning all children with HIV infection included in the Network's database. RESULTS: In this Network centralized HIV specialists work with primary care practitioners throughout Wisconsin to assure that children with HIV infection have access to care of uniform quality no matter where they live. Network staff care for children with HIV infection both directly and through the education and support of primary care providers. Care requirements are outlined in a state-published protocol supplied to practitioners. Audit of care is possible because of a centralized data collection system, and ongoing feedback and education occur via the activities of nursing care coordinators and both hospital- and community-based social workers. CONCLUSIONS: This system of care may serve as a model for care delivery to children with HIV infection in low prevalence areas and may be applicable to the care of children with other chronic diseases being cared for in a managed care environment.

Adult↗

Lifetime cost of care for children with human immunodeficiency virus infection.

BACKGROUND: Knowledge of the cost of care for children with HIV infection is necessary to analyze the economic impact of recommendations for universal counseling and voluntary HIV testing of pregnant women. OBJECTIVES: To estimate the total cost of care for children with HIV infection. METHODS: We performed a retrospective cohort study of all 88 children with (n = 29) or at risk for (n = 59) perinatally acquired HIV infection cared for at Children's Hospital of Wisconsin between February 2, 1987, and June 1, 1995. Review of medical records for all 29 children with perinatally acquired HIV infection or AIDS identified: date of HIV diagnosis; date of classification into Category N, A, B or C; date of AIDS diagnosis; and date of death or transfer of care. The time each subject remained in each CDC category was calculated and the Kaplan-Meier product-limit method was used to calculate survival time for all patients in each CDC category. Hospital-based inpatient and outpatient charges per patient per month in each CDC category (N, A, B, C and AIDS) were calculated with information from the hospital financial services database, and lifetime hospital-based inpatient and outpatient charges were estimated as the sum of the charges for each category. From that, total charges were calculated assuming that hospital-based charges were 83% of total charges. RESULTS: Based on a median survival time of 120 months, the mean lifetime charges for hospital-based care for children with HIV infection was $408307 (estimates ranged from $172217 to $498539). If hospital-based care represents 83% of the total charges for care of children with HIV infection, then mean total lifetime charges for care of children with HIV infection were $491936 ($207490 to $600649). CONCLUSIONS: The care of children with HIV infections is expensive. This information may be useful in planning for care programs and for analyzing the economic impact of recommendations for universal counseling and voluntary HIV testing of pregnant women.

Child↗

Effectiveness of intensive nurse case management in decreasing vertical transmission of human immunodeficiency virus infection in Wisconsin.

BACKGROUND: During a clinical trial (ACTG Study 076), perinatal HIV transmission was reduced by two-thirds when pregnant women with HIV infection and their infants were treated with zidovudine (ZDV). A similar benefit has not been uniformly found in practice settings. OBJECTIVES: To measure the effectiveness of a nurse case management system in supporting prenatal ZDV use in women with HIV infection and their infants and in decreasing perinatal HIV transmission. METHODS: We performed a retrospective cohort study of all children with or at risk for HIV infection cared for in the Wisconsin HIV Primary Care Support Network. The Network uses intensive nurse case management to optimize the care of pregnant women with HIV infection and their children. For children born between January 1, 1992, and April 30, 1996, we measured the association of prenatal case management by a Network nurse with (1) ZDV use by pregnant women with HIV infection and (2) the rate of vertical HIV transmission. RESULTS: In the 26 months after March 1, 1994 (shortly after the release date of ACTG 076 results), 5 of 39 (13%) infants born to women with HIV infection and enrolled in the Network acquired HIV perinatally compared with 12 of 30 (40%) infants in the 26 months preceding March 1, 1994 (P = 0.01). Between March 1, 1994, and April 30, 1996, 25 of 25 (100%) women whose prenatal care included intensive case management by a Network nurse were treated with prenatal orally administered ZDV, compared with 3 of 14 (21%) women whose prenatal care did not include Network case management (P < 0.0001). There were 2 of 25 (8%) infants who acquired HIV infection in the former group, compared with 3 of 14 (21%) in the latter group (P = 0.2) CONCLUSIONS: Perinatal transmission of HIV was significantly decreased following implementation of national recommendations for ZDV treatment of pregnant women. Prenatal care that included case management by a specialized nurse was significantly more likely to result in appropriate ZDV therapy in women and showed a trend toward a lower rate of HIV infection in their infants, compared with prenatal care that did not include such personnel.

Adult↗

Failure of aggressive therapy to alter outcome in pediatric near-drowning.

OBJECTIVES: To identify predictors of outcome in pediatric near-drowning victims, and to measure the effectiveness of therapy in pediatric near-drowning victims by assessing clinical outcome as a function of injury severity at presentation and therapeutic interventions during hospitalization. DESIGN: Retrospective chart review at a tertiary care university associated Children's Hospital from January 1976 to July 1992. MEASUREMENTS AND MAIN RESULTS: Initial intensive care unit (ICU) assessment included a Glasgow Coma Score (GCS) and a Pediatric Risk of Mortality (PRISM) Score. Outcome was assessed using a standard scoring system classifying functional abilities at hospital discharge as no functional disability, independent, partially independent, or total dependence on caregivers for function. Forty (49%) of 81 died. Of the survivors, 26 (63%) had no functional disability or were partially dependent at hospital discharge. Of the 47 (64%) patients with a GCS < or = 4 on presentation to the ICU, 37 (79%) died and 10 (21%) were dependent in all areas of function at discharge. Of the 40 (60%) patients who had a PRISM score < 20, 98% either died or were completely dependent at discharge. Of the 49 patients who were asystolic upon arrival to the emergency department (ED), 76% died, and the rest were completely dependent. Logistic regression showed that therapy had no independent effect on outcome when disease severity was accounted for. CONCLUSIONS: Severity of illness measured by GCS and PRISM score in the ICU can be useful in predicting outcome. For patients cared for in a Pediatric Intensive Care Unit, those with asystole on arrival at the ED had uniformly poor outcome. Currently available therapies do not alter outcome.

Adolescent↗

Survival and functional outcome of children requiring mechanical ventilation during therapy for acute bacterial meningitis.

OBJECTIVE: To determine predictors of survival and functional outcome of pediatric patients requiring mechanical ventilation during therapy for acute bacterial meningitis. DESIGN: Retrospective case series. SETTING: Pediatric intensive care unit (ICU) at a midwestern tertiary care children's hospital. PATIENTS: Consecutive sample of 32 patients (median age 9.8 months; range 9 days to 12 yrs) from 1985 to 1990 with acute bacterial meningitis severe enough to require mechanical ventilation during therapy. Of these patients, 59% were female and 59% were white. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Data were analyzed to identify predictors of survival and functional status after hospital discharge. Variables included were vital signs, Pediatric Risk of Mortality (PRISM) score within the first 24 hrs of hospitalization, Glasgow Coma Score, and course of illness. Functional status was assessed at hospital discharge and at follow-up (median follow-up: 41.5 months, range 7 to 77) in the areas of locomotion, self-care, and communication. There were ten inhospital deaths. The 22 survivors formed three groups. At hospital discharge, seven children showed no functional disability. Seven patients were dependent in all three areas of function at discharge, with six still dependent at follow-up evaluation. Eight patients showed mild to moderate impairment in at least one area of function at hospital discharge. At follow-up, four of these eight patients demonstrated no functional disability, one had improved status, two were unchanged, and one was lost to follow-up. The best predictor of death and functional status at follow-up was the admission PRISM score. Hypotension and tachycardia within the first 24 hrs after pediatric ICU admission were strongly associated with poor outcome. CONCLUSIONS: After bacterial meningitis in children whose care included mechanical ventilation, half of the patients died or survived with severe functional deficits. Patients with mild or moderate functional deficits at hospital discharge improved with time.

Acute Disease↗

Comparison of four different methods for detection of Cryptosporidium species.

Newly available assays offer alternatives to conventional microscopic examination for Cryptosporidium spp. We compared two enzyme immunoassays, ProSpect Cryptosporidium microtiter assay (Alexon, Inc., Mountain View, Calif.) and Color Vue Cryptosporidium assay (Serady, Indianapolis, Ind.), and a direct immunofluorescent assay, Merifluor Cryptosporidium kit (Meridian Diagnostics, Cincinnati, Ohio), with acid-fast Kinyoun-staining for the detection of Cryptosporidium spp. Examinations were performed on 129 stool specimens received from patients during a recent waterborne outbreak. A specimen was considered positive when organisms could be identified visually by acid-fast and immunofluorescent stains or if organisms could be visualized by either acid-fast or immunofluorescent stain and detected by both enzyme immunoassays. The final number of positive specimens was 55. No single procedure detected all 55 positive specimens. Of these, ProSpect and Color Vue detected 52 (sensitivity, 94.5%), and the Kinyoun stain and Merifluor detected 53 (sensitivity, 96.4%). The final number of negative specimens was 74. One false-positive result was seen with both the Kinyoun stain and the ProSpect assay. The Color Vue and ProSpect assays required the most hands-on technologist time. The ProSpect assay and Merifluor kit were easiest to perform. The acid-fast stain was difficult to interpret. The Merifluor kit was easiest to read and was adaptable to both batch and single testing. Overall, the Kinyoun stain and the Merifluor test were preferable to both of the enzyme immunoassays because of the high reagent cost and hands-on time required for the enzyme immunoassays. The difficult interpretation of the Kinyoun stain smears made the Merifluor a more desirable test despite its higher cost. We conclude that all methods tested were equally sensitive and specific for the detection of Cryptosporidium spp. Ease of use, adaptability to batch testing, and cost are important criteria in determining the method of choice.

Animals↗

Predicting death in pediatric patients with acute respiratory failure. Pediatric Critical Care Study Group. Extracorporeal Life Support Organization.

OBJECTIVE: To estimate mortality risk in pediatric patients with acute hypoxemic respiratory failure (AHRF). DESIGN: Retrospective chart review. SETTING: Forty-one pediatric ICUs. SUBJECTS: Four hundred seventy children with AHRF. We defined AHRF as mechanical ventilation with positive end-expiratory pressure > or = 6 cm H2O and fraction of inspired oxygen greater than or equal to 0.5 for 12 or more hours. MEASUREMENTS: Physiologic and treatment variables were recorded every 12 h for 14 days. Cases were randomly assigned to score development and score validation subsets. Variables were assessed for their association with mortality in the development subset by logistic regression analysis. The analysis generated a series of logistic equations, which we called the Pediatric Respiratory Failure (PeRF) score, to estimate mortality risk at 12-h intervals over the first 7 days of treatment for AHRF. The predictive ability of the score was assessed in the validation subset by receiver operating characteristic curve area and goodness-of-fit chi 2. RESULTS: Mortality of the collected cases was 43%. The PeRF score included age, operative status, Pediatric Risk of Mortality score, fraction of inspired oxygen, respiratory rate, peak inspiratory pressure, positive end-expiratory pressure, PaO2, and PaCO2. Area under the receiver operating characteristic curve was 0.769 at entry and increased to greater than 0.8 after 36 h. When the score was applied to the validation subset of patients, goodness-of-fit chi 2 showed no significant difference between estimated and actual mortality between 0 and 96 h. CONCLUSIONS: The PeRF Score accurately estimated mortality risk in this retrospectively sampled group of high-risk pediatric patients with AHRF. This score may be useful in studies of newer therapies for pediatric AHRF, though prospective validation is necessary before it could be used to make clinical decisions.

Adolescent↗

A cluster of anaphylactic reactions in children with spina bifida during general anesthesia: epidemiologic features, risk factors, and latex hypersensitivity.

BACKGROUND: Anaphylactic reactions (ARs) in high-risk pediatric patients undergoing general anesthesia, especially those with spina bifida, have been attributed to anesthetics, muscle relaxants, antimicrobials, ethylene oxide, and latex. METHODS: To identify risk factors for AR during general anesthesia and to investigate the role of latex allergy, we studied epidemiologic and immunologic characteristics of patients with ARs during general anesthesia during a 13-month cluster of such reactions at Children's Hospital of Wisconsin (case patients). Patients with AR were compared with patients with spina bifida undergoing uneventful general anesthesia during the same period (control patients). For each case patient and control patient, we conducted a chart review; a parental interview; skin prick testing with latex, anesthetics, aeroallergens, and banana extract; ELISA and RAST for latex-specific IgE; a total serum IgE; and an ELISA for IgE antibody to ethylene oxide. RESULTS: Anaphylactic reactions occurred exclusively in patients with spina bifida (n = 10) or patients with a congenital urinary tract anomaly (n = 1). Case-patients were more likely than control patients to have a history of asthma (p = 0.002), rubber contact allergy (p = 0.001), food allergy (p = 0.001), rash caused by adhesive tape (p = 0.05), daily rectal disimpaction (p < 0.001), nine or more prior surgical procedures (p < 0.002), latex-specific IgE (p = 0.027), or elevated total serum IgE levels (p = 0.002). Multivariate analysis identified non-white race, rubber contact allergy, history of food allergy, and nine or more surgical procedures as significant independent risk factors. Logistic model equation identified the predicted probability of AR with a sensitivity, specificity, and positive predictive value of 82%, 97%, and 82%, respectively. CONCLUSIONS: These findings demonstrate that atopy, especially symptomatic latex allergy, is associated with AR during anesthesia in patients with spina bifida. Until a standardized latex test is available, a medical history of immediate rubber contact allergy, non-white race, food allergy, or nine or more prior surgical procedures can identify patients with spina bifida at highest risk for ARs. A complete history, including rubber contact and food allergy, should be compiled on all patients with spina bifida before surgery.

Anaphylaxis↗

Assessing the need for anaerobic medium for the recovery of clinically significant blood culture isolates in children.

We examined the sensitivity of several BACTEC media options for the detection of bacteremia and fungemia in children at two pediatric health care facilities. At one institution a single aerobic bottle containing PEDS Plus medium was as sensitive in identifying positive blood cultures as the combination of aerobic and anaerobic media (77% vs. 80%; P = 1.0). When data from both facilities were combined, a blood culture set containing both aerobic and anaerobic media detected significantly more positive blood cultures than any single aerobic medium. However, the aerobic/anaerobic bottle combination was not significantly better than a blood culture set containing two aerobic media and, in absolute terms, the latter identified more cases of bacteremia. Of the 116 clinically significant episodes of bacteremia identified in this study, only 1 was caused by an anaerobic bacterium. We conclude that the routine use of anaerobic media for blood cultures of pediatric patients might be unnecessary but that the use of two different aerobic media could increase the sensitivity of the BACTEC blood culture system.

Anaerobiosis↗

Increased incidence of HLA-B40 group antigens in children with hemolytic-uremic syndrome.

Hemolytic uremic syndrome (HUS) develops in 25-30% of children infected with Escherichia coli strains that produce Shiga-like toxins, also known as verocytotoxins. Mild HUS also occurs in 1 in 4 of the other family members, suggesting a familial predisposition to HUS. To understand the possible genetic predisposition, the frequency of HLA antigens was evaluated in 30 children (12 boys, 18 girls; mean age 3.8 years) with HUS following a prodrome of bloody diarrhea. When compared to a blood donor population from the same geographic area and ethnic background, no significant differences were noted in the frequency of HLA-A, HLA-C, HLA-DR, and HLA-DQ antigens. However, the frequency of HLA-B40 and its splits (B60, 61, 41, 47) was significantly higher in the study population (corrected p < 0.005). The relative risk of developing HUS was 6.04 when HLA-B40 and HLA-B40 split products were present, and the risk increased to 8.5 when the analysis was extended to include the cross-reactive antigens B44 and B13. These HLA-B antigens share common amino acid sequences at positions 41-45 and 67-74 on the alpha-1 domain of the HLA class I molecule. Our data suggest that the inheritance of HLA-B40, its splits, and cross-reactive antigens increases the risk of developing HUS.

Adolescent↗

Control and variability of gastric pH in critically ill children.

OBJECTIVES: To determine the effect of illness severity and acute central nervous system injury on the control and variability of gastric pH in pediatric intensive care unit (ICU) patients receiving ranitidine. DESIGN: Prospective, descriptive study. SETTING: Pediatric ICU of a children's hospital. PATIENTS: Fourteen pediatric ICU patients. INTERVENTIONS: Ranitidine (4 mg/kg/day) was administered to all patients. MEASUREMENTS AND MAIN RESULTS: Patients enrolled in the study were divided into two groups based on illness type and severity. Illness severity was measured by the Pediatric Risk of Mortality (PRISM) score, with a PRISM score of > or = 20 defining severe illness. Illness type was designated as central nervous system or noncentral nervous system. Gastric pH was continuously monitored in all patients using an intragastric, pH-sensitive electrode. Poor control of gastric pH was defined as a pH of < 4.0 for > 20% of the time monitored. The statistical significance of the differences between groups was measured using the Wilcoxon two-sample test or Fisher's exact test. Patients with severe illness or acute central nervous system injury had a lower mean gastric pH than all other patients (4.6 vs. 6.4; p = .008) and spent more time with a gastric pH of < 4.0 than other patients (47.5% of time monitored vs. 12.5% of time monitored; p = .003). Poor control of gastric pH occurred in 100% of patients with severe illness or acute central nervous system injury, while only 20% of the remaining patients had poor control of gastric pH (p = .01). Using power-spectrum analysis to evaluate gastric pH variability, gastric pH in patients receiving bolus ranitidine was more variable than gastric pH in patients receiving ranitidine continuously (p = .045). Illness severity or type had no effect on gastric pH variability (p = .78). CONCLUSIONS: a) Continuous infusion of ranitidine decreases variability of gastric pH in pediatric ICU patients; b) gastric pH variability may make intermittent monitoring of gastric pH inaccurate; c) children with acute central nervous system injury or PRISM scores of > or = 20 have poor control of gastric pH; d) type of injury and PRISM scores predict response to ranitidine therapy.

Central Nervous System Diseases↗