A threshold neurotoxic amphetamine exposure inhibits parietal cortex expression of synaptic plasticity-related genes

Compulsive drug abuse has been conceptualized as a behavioral state where behavioral stimuli override normal decision making. Clinical studies of methamphetamine users have detailed decision making changes and imaging studies have found altered metabolism and activation in the parietal cortex. To examine the molecular effects of amphetamine (AMPH) on the parietal cortex, gene expression responses to amphetamine challenge (7.5 mg/kg) were examined in the parietal cortex of rats pretreated for nine days with either saline, non-neurotoxic amphetamine, or neurotoxic AMPH dosing regimens. The neurotoxic AMPH exposure [three doses of 7.5 mg/kg/day AMPH (6 h between doses), for nine days] produced histological signs of neurotoxicity in the parietal cortex while a non-neurotoxic dosing regimen (2.0 mg/kg/day x 3) did not. Neurotoxic AMPH pretreatment resulted in significantly diminished AMPH challenge-induced mRNA increases of activity-regulated cytoskeletal protein (ARC), nerve growth-factor inducible protein A (NGFI-A), and nerve growth-factor inducible protein B (NGFI-B) in the parietal cortex while neither saline pretreatment nor non-neurotoxic AMPH pretreatment did. This effect was specific to these genes as tissue plasminogen activator (t-PA), neuropeptide Y (NPY) and c-jun expression in response to AMPH challenge was unaltered or enhanced by amphetamine pretreatments. In the striatum, there were no differences between saline, neurotoxic AMPH, and non-neurotoxic AMPH pretreatments on ARC, NGFI-A or NGFI-B expression elicited by the AMPH challenge. These data indicate that the responsiveness of synaptic plasticity-related genes is sensitive to disruption specifically in the parietal cortex by threshold neurotoxic AMPH exposures.

Imatinib mesylate therapy in advanced gastrointestinal stromal tumors—A Regional cancer centre experience

19505

Background: The treatment of gastrointestinal stromal tumors has been revolutionised by the advent of Imatinib, a specific tyrosine kinase inhibitor. Post operative local and metastatic recurrences of this tumor have been effectively managed by Imatinib. Here we present our experience of Imatinib in recurrent locally advanced/metastatic gastrointestinal stromal tumors (GIST). Methods: From Nov 2001 to Sep 2005, 33 patients with metastatic and / or locally advanced inoperable CD-117 positive GIST were offered imatinib mesylate therapy at 400 mg/day p.o. A total of 21 patients were evaluable for tumor response. Follow up period ranged from 4 months to 38 months with median follow up period being 18 months. Median age is 58 yrs, M:F ratio is 6:4. ECOG performance status was 0–1 in 70% (23 patients) and 2 in 30% (10 patients). 70% patients had post surgery recurrence. 2 patients (6%) had received adjuvant chemotherapy prior to recurrence. 30% (10 patients) had local recurrence, 40% (13 patients) had metastatic disease while 30% (10 patients) had local recurrence as well as metastatic disease. Results: Response evaluation was done by RECIST criteria. 15% (5 patient) showed CR while PR rates were 30% (10 patients). The overall major response (CR+PR) was 45%. The overall progression free survival was as high as 80%. All the patients who had a progression free survival also had a significant improvement in quality of life. Conclusions: Imatinib mesylate therapy shows significant survival benefits in locally advanced inoperable/metatstatic gastrointestinal stromal tumors. It will be a very long time before PET scan for evaluation and follow up becomes feasible in developing country setting.

No significant financial relationships to disclose.

Childhood nasopharyngeal carcinoma: A 4-year single institution experience

9069

Background: Pediatric nasopharyngeal carcinoma (PNC) represents a locally advanced undifferentiated tumor. In this study, clinical experience and therapeutic results of 24 children with newly diagnosed PNC, treated in a single oncology institution in India over a period of 5 years, are analyzed. Methods: 24 patients (23 males and 1 female) 7–14 years old (median = 12) from Jan 2000 to Sep 2005 with PNC were retrospectively evaluated. 18/24 patients were evaluable. 16 patients received induction chemotherapy followed by radiotherapy while 1 patient was offered concurrent chemoradiotherapy, 1 patient received radiotherapy alone. 15/16 patients received postradiation chemotherapy. The agents used in induction and adjuvant therapy were cisplatin (100 mg/m2) on day 1 and 5-fluorouracil 750 mg/m2 for 5 days. The dose of radiotherapy used was 60 gray in 30 fractions. Results: The time of onset of symptoms to diagnosis ranged from 1 month to 9 months with a median of 5.5 months. Histopathology was lymphoepithelioma in 5 patients (27.7%) while 13 patients (72.2%) had poorly differentiated carcinoma. Disease extent was T2 (n = 7), T3 (n = 6), and T4 (n = 5); N1 (n = 5), N2 (n = 7), and N3 (n = 5). 7 patients had intracranial invasion. None had metastatic disease on presentation. 13 patients (72.2%) achieved major response which included 7 (38.8%) complete remission and 6 (33.3%) partial remission after the induction chemotherapy and radiotherapy. 4 (22.2%) had progressive disease. Another 3 (16.6%) attained complete remission after post radiation chemotherapy which consisted of two cycles of cisplatin and 5-flourouracil. The follow up ranged from 5 months to 84 months with a median follow up of 35 months. The disease free survival ranged from 10 months to 53 months with a median of 33 months. The patients who had a better response to induction chemotherapy had a better disease free survival. Out of 7 patients who attained complete remission 2 relapsed with a median time to first relapse of 9.5 months. Toxicity to therapy was modest. Only one patient had grade 4 neutropenia and mucositis. There was no therapy related mortality. Conclusion: Chemoradiotherapy for nasopharyngeal carcinoma in children is an effective treatment modality with minimal toxicity.

No significant financial relationships to disclose.

Central venous access in the pediatric cancer patient—Problems unique to developing countries: 5-year experience at a regional cancer center in Western India

9049

Background: Central venous catheter (CVC) is required in the pediatric cancer patient for chemotherapy administration and supportive care. This study was carried out to review our experience with CVC, with special reference to issues unique to developing countries. Methods: 178 children who underwent 181 CVC insertions at our institute between January 2001 and October 2005 were retrospectively analysed for demographics, diagnosis, type of CVC, infective and non infective complications. Continuous data were assessed using the t test or the Wilcoxon rank sum test and categorical data by the chi square test or the Fisher’s exact test. Results: Median age was 6.5 years (0.6–13 yr). Commonest diagnosis was acute lymphoid leukemia (ALL) (n=60). CVC used were Hickman (n=162), subcutaneous ports (n=9) and peripherally inserted central catheters (n=10). Patients with hickman catheters had 164 insertions for 162 patients with a total of 14,090 catheter days, an average of 86.9 days/catheter. There were 5.36 culture positive infections /1000 catheter days. The commonest isolate was Coagulase negative S. Aureus (CNS) (44/80 cases). CVC infection with CNS was associated with higher risk of recurrent infections (OR=3.5 {95%CI=2.12–8.23} p=0.01). Patients having recurrent CVC infections received antibiotics for a median of 9.4 days as against a median of 10 days for those with non-recurrent infections (p=0.01, Wilcoxon rank sum). In 58 ALL patients, early (within 15 days of induction) insertion of CVC was associated with increased risk of culture positive infection as against late (after 15 days of induction) insertion (OR=2.3, 95%CI=1.0–5.2, p=0.05). Other complications were thrombosis (n=3), exit-site infection (n=5), tunnel infection (n=3), catheter fracture (n=1) and dislodgement (n=3). Conclusions: As most patients do not afford port, Hickman is the most preferred CVC in pediatric oncology in a developing country. Most patients are of low literacy and poor socioeconomic status. This is reflected in significantly high rates of CVC infection. Communication between the inserting doctor, nursing staff and proper counseling of the patient is the key to reduce complications

No significant financial relationships to disclose.

Poly TLR agonist polyantigenic vaccine (Mycobacterium w) in palliative therapy of head and neck cancer

12512

Background: Poly TLR poly-antigenic vaccine containing Mycobacterium w (Mw) is found useful in the management of lung cancer and bladder cancer when used along with standard therapy1,2 but not in Head and Neck cancer3–4. This study was carried out to evaluate its efficacy as a single agent in advanced head & neck cancer. Methods: In a prospective study consecutive 75 symptomatic patients with advanced head & neck cancer (squamous cell) attending hospital for palliative care following failure of standard therapy were administered Mw once a week for 8 weeks. Results: Of 75 patients 43 were male & 32 females with 76% between the ages of 31 to 60). 18 had buccal mucosa tumor, 12 alveolar and 11 at base of the tongue. Partial response was seen in 27. It was associated with Pain relief (27/27), Healing of ulcer/fistula (4/5), improvement in dysphagia (7/15), improvement in voice(5/19). All 27 showed improvement in constitutional symptoms also. No systemic side effects were seen. Conclusions: Mw vaccine is useful in palliative care of head & neck cancer. Reference 1Sur PK, Dastidar AG. Role of mycobacterium w as adjuvant treatment of lung cancer. J Indian Med Assoc. 2003;101:118, 120. 2Chaudhuri P, Mukhopadhyay S. Bladder preserving approach for muscle invasive bladder cancer–role of mycobacterium w. J Indian Med Assoc. 2003;101:559–60 3M. C. Pant, R. Hadi, R. Prasad, D. Dalela, et al. Role of immuno-therapy as a adjuvant treatment in advance head & neck cancer, patient receiving chemo radiotherapy. Journal of Clinical Oncology 2005; 23, (16S Part 1): 190S 4S. K. Sarkar, C. Dasgupta. Role of Mycobacterium W as an adjuvant treatment of Head & Neck Cancer_A Randomised trial. Journal of Clinical Oncology 2005; 23, (16S Part 1): 521 s.

No significant financial relationships to disclose.

Attitudes of professional anatomists to curricular change

Throughout the world, recent developments in medical curricula have led to marked changes in the teaching of gross anatomy. This change has involved decreasing curricular student contact time and the use of new methods for anatomical teaching. Some "modern" anatomists have welcomed the arrival of these novel methods while other, more "traditional," anatomists have fought to maintain the use of cadaveric dissection. Consequently, controversy over teaching methods has developed to the point that "modernist" and "traditionalist" views within the community of professional anatomists seem to have diverged such that the importance of gross anatomy in the medical curriculum is disputed and that cadaveric dissection by students is no longer the preferred method of teaching. This study tests this hypothesis using Thurstone and Chave attitude analyses to assess attitudes to educational change and the importance of anatomy in medicine and a matrix questionnaire that required professional anatomists to relate course aims to different teaching methods. In total, 112 completed questionnaires were received from anatomists who are employed at higher education institutions that use various teaching methods and who span the academic hierarchy. The results suggest that over 90% of anatomists favor educational change and approximately 98% of professional anatomists believe that gross anatomy has an important role to play in clinical medicine. A clear majority of the anatomists (69%) favored the use of human cadaveric dissection over other teaching methods (this method seeming to achieve a range of different course aims/objectives) (P < 0.001; Kruskal-Wallis). Using Kruskal-Wallis statistical tests, the order-of-preference for teaching methods was found to be as follows: 1. Practical lessons using cadaveric dissection by students. 2. Practical lessons using prosection. 3. Tuition based upon living and radiological anatomy. 4. Electronic tuition using computer aided learning (CAL). 5. Didactic teaching alone (e.g. lectures/class room-based tuition). 6. Use of models. The preference for the use of human cadaveric dissection was evident in all groups of anatomists, whether "traditionalist" or "modernist" (P = 0.002, Chi-squared). These findings are therefore not consistent with our initial hypothesis.

The epidemiology of Kawasaki disease in an urban hospital: does African American race protect against coronary artery aneurysms?

The etiology and pathogenesis of Kawasaki disease (KD) is largely unknown. Certain demographic factors and laboratory findings are predictive of the development of coronary artery (CA) aneurysms. The objectives of this study were to determine the epidemiology of KD patients in an urban hospital and determine risk factors associated with their development of CA abnormalities. A longitudinal case series of KD patients admitted to Children's National Medical Center from 1990 to 2002 was examined. Age, sex, ethnic background, duration of fever prior to diagnosis, address, month diagnosed, and CA abnormalities (ectasia or aneurysms) on echocardiography were recorded. Median household income was obtained from the U.S. Census Bureau Web site. The Student t-test, logistic regression analyses, and the Kruskal-Wallis test were used, with significance assumed at p < 0.05. A total of 302 patients were evaluated. CA abnormalties were found in 27 patients (9%), with aneurysms identified in 13 patients (4%). Age was 2.9 +/- 2.4 years (range, 2 months to 14 years). A total of 51 patients (16%) were < or =1 year and 35 patients (12%) were > or =5 years. Ethnic distribution was 54% (164) African American, 24% (72) Caucasian, 9% (29) Asian/Pacific Islander, 8% (23) Hispanic, and 5% (14) Middle Eastern. Only 2/164 (1.2%) African Americans developed CA aneurysms. Neighborhood median income of the cohort was $45,400 +/- $21,200 ($52,200 +/-$25,800 for patients with aneurysms). A total of 28% of cases clustered between December and January. Cases doubled annually in 1999-2001 compared to 1990-1998 (39 vs 19). Multivariate logistic regression found age between 1 and 5 years [p = 0.045; odds ratio, 0.31; 95% confidence interval (CI), 0.10-0.97] and African American race (p = 0.014; odds ratio, 0.15; 95% CI, 0.03-0.68) to be independently protective against CA aneurysms. Duration of fever prior to diagnosis, considered in 210 patients, was different between patients with and without aneurysms (11 +/- 5.3 vs 6.5 +/- 3.8 days, respectively, p = 0.0007). Multivariate logistic regression found fever longer than 5 days to be the only predictive factor associated with the development of aneurysms and any abnormality. African Americans had a shorter duration of fever than the rest of the cohort (6.03 vs 7.31 days), (p = 0.0087). The epidemiology of KD at our hospital is similar to that at other centers except for the predominance of African Americans with a shorter duration of fever prior to diagnosis and a decreased incidence of CA aneurysms compared to other ethnicities. The protective nature of African American ethnicity against the development of CA aneurysms raises speculation about the role of genetics and its interaction with immunity in the pathogenesis of KD.

Certainty and mortality prediction in critically ill children

OBJECTIVES

The objective of this study is to investigate the relationship between a physician's subjective mortality prediction and the level of confidence with which that mortality prediction is made.

DESIGN AND PARTICIPANTS

The study is a prospective cohort of patients less than 18 years of age admitted to a tertiary Paediatric Intensive Care Unit (ICU) at a University Children's Hospital with a minimum length of ICU stay of 10 h. Paediatric ICU attending physicians and fellows provided mortality risk predictions and the level of confidence associated with these predictions on consecutive patients at the time of multidisciplinary rounds within 24 hours of admission to the paediatric ICU. Median confidence levels were compared across different ranges of mortality risk predictions.

RESULTS

Data were collected on 642 of 713 eligible patients (36 deaths, 5.6%). Mortality predictions greater than 5% and less than 95% were made with significantly less confidence than those predictions <5% and >95%. Experience was associated with greater confidence in prognostication.

CONCLUSIONS

We conclude that a physician's subjective mortality prediction may be dependent on the level of confidence in the prognosis; that is, a physician less confident in his or her prognosis is more likely to state an intermediate survival prediction. Measuring the level of confidence associated with mortality risk predictions (or any prognostic assessment) may therefore be important because different levels of confidence may translate into differences in a physician's therapeutic plans and their assessment of the patient's future.

The effect of intranasal fentanyl on the emergence characteristics after sevoflurane anesthesia in children undergoing surgery for bilateral myringotomy tube placement

Children undergoing placement of bilateral myringotomy tubes (BMT) often exhibit pain-related behavior (agitation) in the postanesthesia care unit. We compared the emergence and recovery profiles of pediatric patients who received sevoflurane with or without supplementary intranasal fentanyl for BMT surgery. By using a prospective, double-blinded design, 150 children 6 mo to 5 yr of age, scheduled for routine BMT surgery, were anesthetized with sevoflurane (2%-3%) in a 60% N(2)O/O(2) gas mixture. Patients were randomized to receive equal volumes of intranasal saline (Control), 1 microg/kg fentanyl or 2 microg/kg fentanyl. A blinded observer evaluated each patient using a previously described 4-point agitation scale and the Steward recovery scale. Response to parental presence was observed after a score of six (full recovery) was achieved on the Steward recovery scale. There were no significant differences among the three groups regarding age, weight, surgeon, duration of anesthesia, or ear condition. Recovery times and emergence characteristic scores were not statistically different. Agitation scores were significantly reduced in the 2-microg/kg Fentanyl group as compared with the Control group (P = 0.012). Fentanyl 2 microg/kg is recommended to reduce the incidence of agitation seen in these patients.

IMPLICATIONS

We examined the use of nasally administered fentanyl for the relief of agitation or discomfort after placement of bilateral myringotomy tubes in 150 children ages 6 mo to 5 yr using a prospective, double-blinded design. Fentanyl 2 microg/kg was found to reduce the incidence of agitation in these patients.

Fast-tracking children after ambulatory surgery

This study was designed to determine the feasibility and benefits of fast-tracking children after ambulatory surgery. One-hundred-fifty-five healthy children undergoing surgical procedures lasting <90 min were studied in a randomized manner. After surgery, children who met predefined recovery criteria in the operating room were entered into one of the study groups. Seventy-one patients (control) were first admitted to the postanesthesia care unit (PACU) and then to the second-stage recovery unit (SSRU). Eighty-four children bypassed the PACU and were directly admitted to the SSRU (Fast-Track group). The demographic data, airway management, and surgical procedures were similar in both groups of patients. During the recovery phase, 62.0% of the PACU group patients and 40.5% of the Fast-Track patients received analgesics (P = 0.01). The total recovery time was 79.1 +/- 48.3 min in the Fast-Track group and 99.4 +/- 48.6 min in the Control group (P = 0.008). A larger percentage of parents in the Fast-Track group (31% vs 16%) reported that their child was restless on arrival at the SSRU (P = 0.037). There were no clinically significant adverse events. However, adequate pain control must be provided before transfer to SSRU. In conclusion, fast-tracking children after ambulatory surgery is feasible and beneficial when specific selection criteria are used.

IMPLICATIONS

The results of this study show that the total recovery time is shorter in children who are fast-tracked (bypass the postanesthesia care unit) after ambulatory surgery. A higher percentage of parents of the Fast-Track group felt that their child was restless on arrival at the second-stage recovery unit. Fast-tracking children after ambulatory surgery is feasible and beneficial when specific selection criteria are used.

Recombinant cytochrome rC557 obtained from Escherichia coli cells expressing a truncated Thermus thermophilus cycA gene. Heme inversion in an improperly matured protein

Cytochrome rC(557) is an improperly matured, dimeric cytochrome c obtained from expression of the "signal peptide-lacking" Thermus thermophilus cycA gene in the cytoplasm of Escherichia coli. It is characterized by its Q(00) (or alpha-) optical absorption band at 557 nm in the reduced form (Keightley, J. A., Sanders, D., Todaro, T. R., Pastuszyn, A., and Fee, J. A. (1998) J. Biol. Chem. 273, 12006-12016). We report results of a broad ranging, biochemical and spectral characterization of this protein that reveals the presence of a free vinyl group on the porphyrin and a disulfide bond between the protomers and supports His-Met ligation in both valence states of the iron. A 3-A resolution x-ray structure shows that, in comparison with the native protein, the heme moiety is rotated 180 degrees about its alpha,gamma-axis; cysteine 14 has formed a thioether bond with the 2-vinyl of pyrrole ring I instead of the 4-vinyl of pyrrole ring II, as occurs in the native protein; and a cysteine 11 from each protomer has formed an intermolecular disulfide bond. Numerous, minor perturbations exist within the structure of rC(557) in comparison with that of native protein, which result from heme inversion and protein-protein interactions across the dimer interface. The unusual spectral properties of rC(557) are rationalized in terms of this structure.

Clinical evaluator reliability for quantitative and manual muscle testing measures of strength in children

Measurements of muscle strength in clinical trials of Duchenne muscular dystrophy have relied heavily on manual muscle testing (MMT). The high level of intra- and interrater variability of MMT compromises clinical study results. We compared the reliability of 12 clinical evaluators in performing MMT and quantitative muscle testing (QMT) on 12 children with muscular dystrophy. QMT was reliable, with an interclass correlation coefficient (ICC) of >0.9 for biceps and grip strength, and >0.8 for quadriceps strength. Training of both subjects and evaluators was easily accomplished. MMT was not as reliable, and required repeated training of evaluators to bring all groups to an ICC >0.75 for shoulder abduction, elbow and hip flexion, knee extension, and ankle dorsiflexion. We conclude that QMT shows greater reliability and is easier to implement than MMT. Consequently, QMT will be a superior measure of strength for use in pediatric, neuromuscular, multicenter clinical trials.

Acute pyelonephritis: comparison of diagnosis with 99mTc-DMSA, SPECT, spiral CT, MR imaging, and power Doppler US in an experimental pig model

PURPOSE

To compare the sensitivity and specificity of technetium-99m dimercaptosuccinic acid (DMSA) single photon emission computed tomography (SPECT), spiral computed tomography (CT), magnetic resonance (MR) imaging, and power Doppler ultrasonography (US) for the detection and localization of acute pyelonephritis by using histopathologic findings as the standard of reference.

MATERIALS AND METHODS

Bilateral vesicoureteric reflux was surgically created in 35 piglets (70 kidneys). One week later, a liquid bacterial culture of Escherichia coli was injected into the bladder. Three days after induction of urinary infection, imaging studies were performed, and the kidneys were removed for histopathologic examination. SPECT images were obtained 2-3 hours after injection of 99mTc-DMSA. Transverse and coronal MR images were obtained with gadolinium-enhanced fast inversion recovery. Transverse CT images were obtained before and after injection of contrast agent. Power Doppler US was performed in longitudinal, transverse, and coronal planes. Each kidney was divided into three zones for correlation of findings.

RESULTS

Histopathologic examination revealed pyelonephritis in 102 zones in 38 kidneys. Sensitivity and specificity for detecting pyelonephritis in the kidneys were 92.1% and 93.8% for SPECT, 89.5% and 87.5% for MR imaging, 86.8% and 87.5% for CT, and 74.3% and 56.7% for US. Sensitivity and specificity for detecting pyelonephritis in the zones were 94.1% and 95.4% for SPECT, 91.2% and 92.6% for MR imaging, 88.2% and 93.5% for CT, and 56.6% and 81.4% for US. The pairwise comparison of these modalities showed no statistically significant difference among them except for US.

CONCLUSION

99mTc-DMSA SPECT, spiral CT, and MR imaging appear to be equally sensitive and reliable for the detection of acute pyelonephritis; power Doppler US is significantly less accurate.

Integrity of thermus thermophilus cytochrome c552 synthesized by Escherichia coli cells expressing the host-specific cytochrome c maturation genes, ccmABCDEFGH: biochemical, spectral, and structural characterization of the recombinant protein

We describe the design of Escherichia coli cells that synthesize a structurally perfect, recombinant cytochrome c from the Thermus thermophilus cytochrome c552 gene. Key features are (1) construction of a plasmid-borne, chimeric cycA gene encoding an Escherichia coli-compatible, N-terminal signal sequence (MetLysIleSerIleTyrAlaThrLeu AlaAlaLeuSerLeuAlaLeuProAlaGlyAla) followed by the amino acid sequence of mature Thermus cytochrome c552; and (2) coexpression of the chimeric cycA gene with plasmid-borne, host-specific cytochrome c maturation genes (ccmABCDEFGH). Approximately 1 mg of purified protein is obtained from 1 L of culture medium. The recombinant protein, cytochrome rsC552, and native cytochrome c552 have identical redox potentials and are equally active as electron transfer substrates toward cytochrome ba3, a Thermus heme-copper oxidase. Native and recombinant cytochromes c were compared and found to be identical using circular dichroism, optical absorption, resonance Raman, and 500 MHz 1H-NMR spectroscopies. The 1.7 A resolution X-ray crystallographic structure of the recombinant protein was determined and is indistinguishable from that reported for the native protein (Than, ME, Hof P, Huber R, Bourenkov GP, Bartunik HD, Buse G, Soulimane T, 1997, J Mol Biol 271:629-644). This approach may be generally useful for expression of alien cytochrome c genes in E. coli.

Relevance of diagnostic diversity and patient volumes for quality and length of stay in pediatric intensive care units

OBJECTIVE

Investigation of associations of the diagnostic diversity and volumes with efficiency and quality of care.

DESIGN

Prospective observational study.

SETTING

Thirty-two pediatric intensive care units (PICUs), 16 selected by random cluster sampling, and 16 volunteering.

PATIENTS

Consecutive admissions of 11,165 patients.

MEASUREMENTS AND MAIN RESULTS

The main outcome measures were length of PICU stay (LOS) and mortality rate, adjusted by generalized linear regression and multivariate logistic regression, respectively. Each diagnosis was categorized into 21 predefined, mutually exclusive categories. Diagnostic diversity of each PICU was characterized by an information-theoretical measure (entropy). For a patient-level analysis, the associations of this measure and PICU patient volume with outcomes were using regression models. For an institution-level analysis, the outcome measures of each PICU were adjusted using ratios of observed/predicted (by the regression models) values, and the associations of these ratios with diagnostic diversity and patient volume were investigated using linear bivariate regressions. Diagnostic diversity ranged in the PICUs from 0.823 to 0.928, when standardized to the uniform distribution with entropy of 1. Congenital heart diseases (12.6%) head traumas (11.5%), other central nervous system conditions (9.7%), and pneumonias (8.7%) constituted the largest diagnostic categories. Patient-level analysis indicated that longer adjusted LOS was associated with larger diagnostic diversity (p <.0001) and lower admission volumes (p <.0001). However, for a given increase in diagnostic diversity, a large LOS increase was associated with low-volume, but not high-volume units. Severity-adjusted mortality rates were inversely related (p =.036) only with admission volumes, but not diagnostic mix. Institution-level standardized LOS ratios correlated with diagnostic diversity (r2 = 0.145; p =.031). Institution-level standardized mortality ratios were inversely related (r2 = 0.123; p =.049) with admission volumes.

CONCLUSIONS

Patient volumes encountered in a PICU are important for maintaining quality and efficiency of care. In low-volume units, fewer diagnoses and higher volumes were both associated with higher efficiencies. In high volume units, diagnosis-specific volumes were generally large enough for achieving diagnosis-independent efficiency. Diagnostic mix was not associated with PICU mortality ratios, but higher PICU volumes were associated with lower mortality rates.

Sudden infant death syndrome in child care settings

BACKGROUND

The incidence of sudden infant death syndrome (SIDS) in the United States has decreased with decreased prone sleeping. Extrapolating from Census Bureau data, approximately 7% of SIDS should occur in organized child care settings (ie, child care centers or family child care homes). However, 2 states have reported higher rates of SIDS in child care.

OBJECTIVES

To determine the percentage of SIDS deaths occurring in child care settings, and to ascertain associated factors.

DESIGN

A retrospective study of SIDS deaths from January 1995 through June 1997 was conducted. Data were abstracted from SIDS databases in 11 states. Characteristics of SIDS cases occurring in child care settings, including sleep position, were compared with those occurring in the care of parents. Univariate and multiple logistic regression analyses were performed.

RESULTS

A total of 1916 SIDS cases were analyzed for this study. Of these deaths, 20.4% occurred in child care settings. Compared with deaths in the care of parents, those occurring in child care settings were more likely to occur on weekdays between 8:00 AM and 4:00 PM; infants were older; not black; and their mothers were more educated. Infants in child care were more likely to be found prone in univariate analysis, but the association was not significant in multiple logistic regression analysis. However, in multiple regression analysis, infants in child care were more likely to be last placed prone or found prone, when the usual sleep position was side or supine.

CONCLUSION

A large proportion (20.4%) of SIDS cases occur in child care settings. Factors associated with SIDS in child care settings include older age, race, and highly educated parents. Previous studies have reported that unaccustomed prone sleeping puts infants at high risk for SIDS; this characteristic was found to be associated with SIDS in child care and may partly explain the high proportion of SIDS cases in child care settings. Parents must discuss sleep position with any caretakers of their infants. In addition, further efforts to educate child care providers about the importance of supine sleep for infants must be ongoing.

Combining physician's subjective and physiology-based objective mortality risk predictions

OBJECTIVE

None of the currently available physiology-based mortality risk prediction models incorporate subjective judgements of healthcare professionals, a source of additional information that could improve predictor performance and make such systems more acceptable to healthcare professionals. This study compared the performance of subjective mortality estimates by physicians and nurses with a physiology-based method, the Pediatric Risk of Mortality (PRISM) III. Then, healthcare provider estimates were combined with PRISM III estimates using Bayesian statistics. The performance of the Bayesian model was then compared with the original two predictions.

DESIGN

Concurrent cohort study.

SETTING

A tertiary pediatric intensive care unit at a university affiliated children's hospital.

PATIENTS

Consecutive admissions to the pediatric intensive care unit.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

For each of the 642 consecutive eligible patients, an exact mortality estimate and the degree of certainty (continuous scale from 1 to 5) associated with the estimate was collected from the attending, fellow, resident, and nurse responsible for the patient's care. Bayesian statistics were used to combine the PRISM III and certainty weighted subjective predictions to create a third Bayesian estimate of mortality. PRISM III discriminated survivors from nonsurvivors very well (area under curve [AUC], 0.924) as did the physicians and nurses (AUCs attendings, 0.953; fellows, 0.870; residents, 0.923; nurses, 0.935). Although the AUCs of the healthcare providers were not significantly different from the AUCs of PRISM III, the Bayesian AUCs were higher than both the healthcare providers' AUCs (p < or = .09 for all) and PRISM III AUCs. Similarly, the calibration statistics for the Bayesian estimates were superior to the calibration statistics for both the healthcare providers and PRISM III models.

CONCLUSIONS

The results of this study demonstrated that healthcare providers' subjective mortality predictions and PRISM III mortality predictions perform equally well. The Bayesian model that combined provider and PRISM III mortality predictions was more accurate than either provider or PRISM III alone and may be more acceptable to physicians. A methodology using subjective outcome predictions could be more relevant to individual patient decision support.

Risk assessment and standardized nosocomial infection rate in critically ill children

OBJECTIVES

To develop and validate a pediatric nosocomial infection risk (PNIR) assessment model, and to compare the daily trends in risk factors between patients with nosocomial infection (cases) and without nosocomial infection (controls) in the pediatric intensive care unit (ICU).

DESIGN

Prospective cohort.

SETTING

A 16-bed pediatric ICU in an urban, university-affiliated, multidisciplinary, regional referral center.

PATIENTS

Patients available for study included consecutive admissions to the unit between May 1, 1992, and April 30, 1993, and between May 9, 1995, and December 11, 1995. Patients from both data collection periods were pooled and randomly divided into training (70%) and validation (30%) samples.

MEASUREMENTS AND MAIN RESULTS

In the logistic regression analysis using admission day data, three factors were shown to remain as independent risk factors. Invasive device use, parenteral nutrition, and the interaction between severity of illness-modified Pediatric Risk of Mortality III-24 score and postoperative care were associated with 2, 6, and 1.5 times the risk of developing nosocomial infection, respectively. This PNIR model performed well in both the training and validation samples as indicated by the goodness-of-fit test, which evaluated standardized nosocomial infection rates (observed vs. predicted nosocomial infection rates). The internal validity of the PNIR model was good. In trend analysis, severity of illness and invasive device use appear to have similar trend patterns, during the first week of pediatric ICU stay. There was no difference in any of these risk factors between cases and controls after 7 days of pediatric ICU stay.

CONCLUSIONS

The PNIR assessment model incorporates intrinsic factors, such as patient severity of illness, and extrinsic factors contributing to the development of nosocomial infection in this high-risk population. The methodology using intrinsic and extrinsic factors to adjust for nosocomial infections should be taken into consideration when evaluating interhospital comparison of nosocomial infection rates, quality assessment, intervention strategies, and use of treatment modalities.

Peripheral venous access ports: outcomes analysis in 109 patients

PURPOSE

To perform a retrospective outcomes analysis of central venous catheters with peripheral venous access ports, with comparison to published data.

METHODS

One hundred and twelve central venous catheters with peripherally placed access ports were placed under sonographic guidance in 109 patients over a 4-year period. Ports were placed for the administration of chemotherapy, hyperalimentation, long-term antibiotic therapy, gamma-globulin therapy, and frequent blood sampling. A vein in the upper arm was accessed in each case and the catheter was passed to the superior vena cava or right atrium. Povidone iodine skin preparation was used in the first 65 port insertions. A combination of Iodophor solution and povidone iodine solution was used in the last 47 port insertions. Forty patients received low-dose (1 mg) warfarin sodium beginning the day after port insertion. Three patients received higher doses of warfarin sodium for preexistent venous thrombosis. Catheter performance and complications were assessed and compared with published data.

RESULTS

Access into the basilic or brachial veins was obtained in all cases. Ports remained functional for a total of 28,936 patient days. The port functioned in 50% of patients until completion of therapy, or the patient's expiration. Ports were removed prior to completion of therapy in 18% of patients. Eleven patients (9.9% of ports placed) suffered an infectious complication (0.38 per thousand catheter-days)-in nine, at the port implantation site, in two along the catheter. In all 11 instances the port was removed. Port pocket infection in the early postoperative period occurred in three patients (4.7%) receiving a Betadine prep vs two patients (4.2%) receiving a standard O.R. prep. This difference was not statistically significant (p = 0.9). Venous thrombosis occurred in three patients (6.8%) receiving warfarin sodium and in two patients (3%) not receiving warfarin sodium. This difference was not statistically significant (p = 0.6). Aspiration occlusion occurred in 13 patients (11.7%). Intracatheter urokinase was infused in eight of these patients and successfully restored catheter function in all but two instances. These complication rates are comparable to or better than those reported with chest ports.

CONCLUSION

Peripheral ports for long-term central venous access placed by interventional radiologists in the interventional radiology suite are as safe and as effective as chest ports.

Nosocomial enterococcal infections in children

OBJECTIVES

To identify factors that are associated with an increased risk of nosocomial enterococcal infection in children.

METHODS

A matched case-control study was conducted between January 1989 and July 1993 at the Children's National Medical Center, Washington DC. One control patient for each case was identified. Control patients did not have nosocomial enterococcal infections and were matched with cases on the basis of age and time of admission closest to the case within a three-month period. Data were collected from systematic review of patient medical records. One hundred and one study patients (cases) were matched with 101 control patients. A case was defined as a patient with enterococcal infection who met the Centers for Disease Control and Prevention criteria for nosocomial infection. Microbiology methods included isolation, identification, and antimicrobial susceptibility testing of enterococci from clinical specimens.

RESULTS

Risk factors associated with nosocomial enterococcal infections were determined by multiple conditional logistic regression analyses of the cases and controls. Factors identified were placement of a central line, gastrointestinal tract pathology, and administration of multiple antimicrobial agents. The median duration of antimicrobial therapy prior to diagnosis of nosocomial enterococcal infection was approximately 1 week.

CONCLUSION

The incidence of nosocomial enterococcal infections in children may be controlled by limiting the number of antimicrobial agents administered to hospitalized high risk patients. The importance of our findings is relevant in an era of increasing rates of antimicrobial resistance in nosocomial enterococcal infections.

The impact of prematurity: a perspective of pediatric intensive care units

OBJECTIVE

To evaluate the relative resource use of pediatric intensive care unit (PICU) patients who had been born prematurely.

DESIGN

Nonconcurrent cohort study.

SETTING

Consecutive admissions to 16 voluntary PICUs.

PATIENTS

A total of 431 formerly premature patients (FPP) and 5,319 nonpremature patients.

INTERVENTIONS

None

METHODS

Patients with a history of prematurity and a prematurity-related complication or an anatomical deformity were compared for demographic and resource requirements to a group of non-premature patients by a bivariable logistic regression analysis that controlled for age as a co-morbid factor.

RESULTS

Compared with other patients, FPP were younger (34.9 +/- 2.2 months vs. 72.4 +/- 1.0 months; p < .001), readmitted to the PICU more often during the same hospitalization (11.1% vs. 5.5%; p < .001), used more chronic technologies (ventilators, gastrostomy tubes, tracheostomy tubes, and parenteral nutrition; 30.3% vs. 5.6%; p < .001), and had longer lengths of stay (5.98 +/-0.59 days vs. 3.56 +/- 0.12 days; p = .004). FPP had significantly higher use of ventilators (45.5% vs. 35.0%; p < .007) and lower use of arterial catheters (27.8% vs. 35.9%, p = .006) and central venous catheters (16.9% vs. 20.9%, p = .026) than nonprematures. The need for other PICU resources, including vasopressors, were similar.

CONCLUSIONS

FPP used more chronic and acute care resources than patients who were not prematurely born. Continued improvements in neonatal care will influence change in many aspects of the health care system. This will also affect the delivery of care to the current patient base of the PICU.