Hyperinflation of the left anterior basal segment: a new sign of pectus excavatum severity on CT.

AIM: To describe a new finding in patients with pectus excavatum - left lower lobe anterior basal segment hyperinflation [LABSH]. A secondary objective is to determine the frequency of the new finding and association with pectus excavatum severity. MATERIAL AND METHODS: The study population included 52 children who underwent preoperative computed tomography (CT) for the evaluation of pectus excavatum. A control group of 50 children was obtained after evaluating 137 CT examinations performed for other reasons. Patient age in both groups ranged from 12 to 20 years. The Haller index was calculated for all patients. LABSH was evaluated by visual inspection of lung windows. The difference in mean radiodensity measurements in regions of interest in the left and right anterior basal segments [ΔHU] was calculated. Spirometry was performed in 44 of the patients and the results were compared to Haller index severity and the presence of LABSH. Echocardiography reports were available for 50 children in the pectus excavatum group. RESULTS: LABSH was identified by visual inspection in 15 patients [29%] and was significantly associated with a Haller index >4.0 (p=0.001). ΔHU for the patients with LABSH was 90.2 HU (standard deviation [SD]=37.7) and for the non-hyperinflated group -5.51 (SD=44.63), which was significant (p<0.0001). There was a significant association of LABSH with the pectus excavatum group as compared to the control group. The difference in mean Haller index for children with normal spirometry (4.4, SD=2.7) was not significantly different (p=0.9899) than for children with obstructive disease (4.5, SD=1). There was mild cardiac compression on two echocardiograms. CONCLUSION: LABSH is a new sign associated with pectus excavatum. The sign suggests segmental bronchial compression caused by chest deformity results in segmental air trapping.

Effect of ventilation on cerebral oxygenation in patients undergoing surgery in the beach chair position: a randomized controlled trial.

BACKGROUND: Surgery in the beach chair position (BCP) may reduce cerebral blood flow and oxygenation, resulting in neurological injuries. The authors tested the hypothesis that a ventilation strategy designed to achieve end-tidal carbon dioxide (E'(CO2)) values of 40-42 mm Hg would increase cerebral oxygenation (Sct(O2)) during BCP shoulder surgery compared with a ventilation strategy designed to achieve E'(CO2) values of 30-32 mm Hg. METHODS: Seventy patients undergoing shoulder surgery in the BCP with general anaesthesia were enrolled in this randomized controlled trial. Mechanical ventilation was adjusted to maintain an E'(CO2) of 30-32 mm Hg in the control group and an E'(CO2) of 40-42 mm Hg in the study group. Cerebral oxygenation was monitored continuously in the operating theatre using near-infrared spectroscopy. Baseline haemodynamics and Sct(O2) were obtained before induction of anaesthesia, and these values were then measured and recorded continuously from induction of anaesthesia until tracheal extubation. The number of cerebral desaturation events (CDEs) (defined as a ≥20% reduction in Sct(O2) from baseline values) was recorded. RESULTS: No significant differences between the groups were observed in haemodynamic variables or phenylephrine interventions during the surgical procedure. Sct(O2) values were significantly higher in the study 40-42 group throughout the intraoperative period (P<0.01). In addition, the incidence of CDEs was lower in the study 40-42 group (8.8%) compared with the control 30-32 group (55.6%, P<0.0001). CONCLUSIONS: Cerebral oxygenation is significantly improved during BCP surgery when ventilation is adjusted to maintain E'(CO2) at 40-42 mm Hg compared with 30-32 mm Hg. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT01546636.

A dual contrast injection technique for multidetector computed tomography angiography of Fontan procedures.

Extracardiac and lateral tunnel Fontan palliations result in caval venous return to the branch pulmonary arteries without prior blood mixing in the right atrium. Single contrast injection techniques result in suboptimal pulmonary computed tomography angiography since blood streaming results in asymmetric pulmonary flow of injected contrast. We used a dual injection technique--dorsal foot vein and upper extremity vein to achieve optimal simultaneous opacification of the inferior and superior venae cavae and branch pulmonary arteries. The resulting dataset allowed for excellent 3D volume renderings and multiplanar reformat images useful for stenosis, aneurysm, and metal stent evaluation.

Diaphragmatic hernia.

We describe a case of acute dyspnea in a patient with Marfan syndrome secondary to bowel herniation into the thoracic cavity.

Nontypeable Haemophilus influenzae in the lower respiratory tract of patients with chronic bronchitis.

The frequency of colonization and intracellular localization of nontypeable Haemophilus influenzae (NTHi) in the lower respiratory tract was determined in healthy adults and in clinically stable and acutely ill chronic bronchitis (CB) patients. NTHi was recovered from bronchial wash or bronchial brush specimens in 6 of 23 (26%) stable CB patients and in 1 of 15 (7%) CB patients with a respiratory exacerbation. No NTHi (0 of 26) was recovered from lower tract specimens of healthy adults undergoing anesthesia for elective surgery. Molecular typing of NTHi strains revealed that five of nine patients with stable CB had different strains in upper respiratory tract and bronchial wash/brush specimens collected simultaneously. Four stable patients with CB had different strains recovered on repeat bronchoscopy. These results demonstrate the frequent colonization of the lower airways of stable CB patients with multiple strains of NTHi. Bronchial biopsies also were examined for intracellular NTHi by in situ hybridization and immunofluorescence microscopy. Intracellular NTHi were found in 0 of 7 healthy adults, 8 of 24 patients with clinically stable CB, and 13 of 15 acutely ill CB patients. This observation suggests a role for intracellular infection by NTHi in the pathogenesis of exacerbations of CB.

Pediatric imaging: sedation with an injection formulation modified for rectal administration.

PURPOSE: To determine if rectal sedation with thiopental sodium produced for intravenous administration provides safe and effective sedation for children undergoing diagnostic imaging. MATERIALS AND METHODS: Five hundred twenty-five consecutive children (mean age, 2.7 years +/- 2.2 [SD]) underwent magnetic resonance imaging (n = 425), computed tomography (n = 89), and nuclear medicine (n = 11) examinations after rectal administration of thiopental sodium injection solution. The solution was prepared from thiopental sodium powder mixed with sterile water to create a concentration of 100 mg/mL. The dose ranged from 25 to 40 mg per kilogram of body weight, with a total dose limit of 1.5 g. The percentages of successful sedations and adverse reactions were evaluated on the basis of data collected at the time of the sedation. RESULTS: Sedation was successful in 504 (96%) children. Ten (2%) children experienced desaturation, but only three of the 10 experienced sedation failure. All cases of desaturation were treated successfully with head repositioning, administration of supplemental oxygen, or both. No children experienced vomiting, acute rectal irritation, paradoxical hyperactivity, or prolonged sedation. CONCLUSION: Thiopental sodium sedation for pediatric imaging, with use of a rectal solution prepared from thiopental sodium preparation for intravenous injection, is safe and effective.

CT urograms in pediatric patients with ureteral calculi: do adult criteria work?

BACKGROUND: Secondary signs of urinary obstruction associated with ureteral calculi are useful adjuncts to diagnosis in adults with renal colic evaluated by unenhanced helical CT. OBJECTIVE: Our purpose was to evaluate the frequency of secondary signs of obstruction in children with renal colic undergoing unenhanced helical CT. MATERIALS AND METHODS: Ureteral calculi were identified in 20 of 61 children with acute flank pain examined by unenhanced helical CT. Each imaging study was evaluated for the presence of secondary signs of urinary obstruction. The frequencies of individual signs were compared with each other by means of the McNemar test. RESULTS: Six children had no secondary sign identified. In the remaining 14 children, proximal ureteral dilatation was seen in 10, renal enlargement in 10, hydronephrosis in 9, tissue rim sign in 6, decreased kidney attenuation in 5, and perinephric stranding in 1. Comparison of the frequencies strongly suggested that perinephric stranding occurs less frequently than proximal ureteral dilatation (P = 0.004), hydronephrosis (P = 0.008), or renal enlargement (P = 0.012). CONCLUSION: Perinephric stranding, a common secondary sign in adults with ureteral calculi, occurs less frequently in children than other reported secondary signs.

The importance of the maximum pulmonary artery regurgitant velocity following repair of tetralogy of Fallot: a pilot study.

BACKGROUND: Tetralogy of Fallot repairs invariably result in pulmonary regurgitation with the long term sequelae of ventricular dilatation and dysfunction. OBJECTIVE: The purpose of this study is to correlate pulmonary flow parameters with right ventricular size and function. MATERIALS AND METHODS: Pulmonary artery velocity was mapped by magnetic resonance flow analysis in seven children with pulmonary regurgitation following tetralogy of Fallot repair. Right and left ventricular volumes were determined by Simpson's rule from double oblique cine gradient echo images of the heart. The ejection fraction was calculated for each ventricle. Right ventricular enlargement was normalized for patient size by calculating the ratios of right ventricle end diastolic and end systolic volumes to the left ventricle end diastolic and end systolic volumes respectively (EDV RV:LV and ESV RV:LV). The maximum pulmonary artery antegrade and retrograde velocities and the ratio of the time for antegrade to regurgitant flow were compared to ventricular function and volume measurements by regression analysis. RESULTS: A significant linear relationship between the maximum regurgitant pulmonary artery velocity and EDV RV:LV was identified (r2 = 0.82). CONCLUSION: An elevated maximum pulmonary regurgitant velocity correlated well with the degree of right ventricular enlargement in patients following tetralogy of Fallot repair. If the results are verified by a larger study, the maximum pulmonary regurgitant velocity may be substituted for the more cumbersome direct measurement of right ventricular size.

Primary care physicians in Israel: self-perception of their role in the healthcare system and policy makers' and patients' perception of them as gatekeepers.

BACKGROUND: The rapidly increasing costs of healthcare pose a major challenge to many governments, particularly in developed countries. Health policy makers in some Western European countries have adopted the policy of a strong primary healthcare system, partly due to their recognition of the value of primary care medicine as a means to restrain costs while maintaining the quality and equity of healthcare services. In these countries there is a growing comprehension that the role of the family physician should be central, with responsibility for assessing the overall health needs of the individual, for coordination of medical care and, as the primary caregiver, for most of the individual's medical problems in the framework of the family and the community. OBJECTIVES: To describe primary care physicians in Israel from their own perception, health policy makers' opinion on the role PCPs should play, and patients' view on their role as gatekeepers. METHODS: The study was based on three research tools: a) a questionnaire mailed to a representative sample of all PCPs employed by the four sick funds in Israel in 1997, b) in-depth semi-structured interviews with key professionals and policy makers in the healthcare system, and c) a national telephone survey of a random representative sample of patients conducted in 1997. RESULTS: PCPs were asked to rank the importance of 12 primary functions. A total of 95% considered coordination of all patient care to be a very important function, but only 43% thought that weighing economic considerations in patient management is important, and 30.6% thought that 24 hour responsibility for patients is important. Also, 60% of PCPs have undergone specialty training and 94% thought that this training is essential. With regard to the policy makers, most preferred highly trained PCPs (board-certified family physicians, pediatricians and internists) and believed they should play a central role in the healthcare system, acting as coordinators, highly accessible and able to weigh cost considerations. Yet, half opposed a full gatekeeper model. They also felt that the general population has lost faith in PCPs, and that most have a low status and do not have adequate training. Regarding the patients' viewpoint, 40% preferred that the PCP function as their "personal physician" coordinating all aspects of their care and fully in charge of their referrals; 30% preferred self-referral to sub-specialists, and 19% preferred their PCP to coordinate their care but wanted to be able to refer themselves to specialists. CONCLUSIONS: In order to maintain high quality primary care, it is important that all PCPs have board certification. In addition, PCP training systems should emphasize preventive medicine, health promotion, health economy, and cost-effectiveness issues. Efforts should be made to render PCPs a central role in the healthcare system by gradually implementing the elements of the gatekeeper model through incentives rather than regulations.

Initial experience with intravenous pentobarbital sedation for children undergoing MRI at a tertiary care pediatric hospital: the learning curve.

OBJECTIVE: Our purpose is to describe the initial experience with intravenous pentobarbital sedation in children undergoing MRI at a tertiary pediatric hospital to identify errors associated with inexperience. SUBJECTS AND METHODS: The study included the first 100 children sedated with intravenous pentobarbital prior to magnetic resonance examination at a tertiary pediatric hospital. The protocol included a maximum dose of 6 mg/kg administered in three divided doses with the total dose not to exceed 200 mg. Flow sheets documenting vital signs, administered drug doses, and adverse reactions were maintained contemporaneous to sedation. RESULTS: Sedation was successful in 92 children. Of the eight children who failed sedation, three were at least 12 years old and three weighed more than 50 kg. chi2 tests identified significantly greater failure rates in children older than 11 years or weight greater than 50 kg. Two children had prolonged sedation after the maximum suggested dose was exceeded. CONCLUSIONS: The success rate was good, but could have been improved by restricting the use of pentobarbital to children less than 12 years of age and weighing less than 50 kg. Radiologists inexperienced with intravenous sedation should strictly observe the maximum suggested dose of pentobarbital to prevent prolonged sedation.

Assessment of cardiac function: magnetic resonance and computed tomography.

A complete cardiac study requires both anatomic and physiologic evaluation. Cardiac function can be evaluated noninvasively by magnetic resonance imaging (MRI)or ultrafast computed tomography (CT). MRI allows for evaluation of cardiac function by cine gradient echo imaging of the ventricles and flow analysis across cardiac valves and the great vessels. Cine gradient echo imaging is useful for evaluation of cardiac wall motion, ventricular volumes and ventricular mass. Flow analysis allows for measurement of velocity and flow during the cardiac cycle that reflects cardiac function. Ultrafast CT allows for measurement of cardiac indices similar to that provided by gradient echo imaging of the ventricles.

'Bacilli and bullets': William Osler and the antivaccination movement.

Public discourse concerning current vaccination recommendations has dramatically increased. The current battle is not new, having had a lengthy foreshadowing during the 19th and early 20th centuries. Over a 30-year period, a concerted effort to limit the use of smallpox vaccine grew at the very time typhoid vaccines were being developed and advocated for widespread prevention. As a long time advocate for widespread smallpox vaccination and a supporter of the newly tested typhoid vaccine, Sir William Osler entered the public debate at the beginning of World War I. Osler was asked to address the officers and men in the British army on the need for typhoid vaccination. His speech entitled "Bacilli and Bullets" outlined the medical reasons for getting inoculated against typhoid. Osler's strong support for typhoid vaccination of the British troops was met by opposition in Parliament but not by most of the troops. Osler's arguments in support of vaccination failed to respond to the concept of "conscientious objection," which was central to the antivaccinationists' argument. Similar arguments are being propounded by current antivaccination groups.

Respiratory viral infections in adults with and without chronic obstructive pulmonary disease.

A longitudinal cohort study of older adults with chronic obstructive pulmonary disease (COPD) who were stratified by FEV(1) at enrollment was done to define the etiology, frequency, severity, and medical-care impact of respiratory tract viral infections (RTVIs). Controls consisted of a group of subjects of comparable age with the patients. RTVIs were documented in 44% of observed acute respiratory illnesses in control subjects and in 27% of COPD subjects, who were followed for mean periods of 35 and 26 mo, respectively. In this heavily influenza-vaccinated cohort ( approximately 90% vaccinated each year), picornaviruses, parainfluenza viruses, and coronaviruses were most commonly identified. Mean time to return to clinical baseline was approximately 2 wk in each group. Control and COPD subjects with mild airways obstruction (baseline FEV(1) >/= 50% predicted) had few emergency-center visits or hospitalizations. Approximately half of COPD subjects with moderate/severe COPD (baseline FEV(1) < 50% predicted) had at least one emergency-center visit and/or hospitalization for acute respiratory illness. RTVIs were documented in 23% of hospitalizations and in 45% of patients admitted between December and March. RTVIs have a major impact on utilization of health care resources for COPD patients with moderate/severe airways obstruction.

Spectrum of clinical illness in hospitalized patients with "common cold" virus infections.

The viruses associated most frequently with the "common cold" are rhinoviruses and coronaviruses. The first prospective cohort study to determine the prevalence of rhinovirus and coronavirus infections in patients of all ages hospitalized for acute respiratory illnesses is described. Hospital admissions for acute respiratory illnesses were identified, and cell culture for rhinovirus and serologic assays on paired sera for coronaviruses 229E and OC43 were performed. A total of 61 infections with rhinoviruses and coronaviruses were identified from 1198 respiratory illnesses (5.1%); in addition, 9 additional infections associated with >/=1 other respiratory viruses were identified. Of those infected with only rhinovirus or coronavirus, underlying cardiopulmonary diseases were present in 35% of the patients aged <5 years, in 93% aged between 5 and 35 years, and in 73% aged >35 years. The predominant clinical syndromes varied by age: pneumonia and bronchiolitis in children aged <5 years; exacerbations of asthma in older children and young adults; and pneumonia and exacerbations of chronic obstructive pulmonary disease and congestive heart failure in older adults. Therefore, rhinovirus and coronavirus infections in hospitalized patients were associated with lower respiratory tract illnesses in all age groups.

A randomized trial of interferon alpha therapy for HIV type 1 infection.

The immunologic and virologic efficacy and safety of interferon a (IFN-alpha) administered in combination with zidovudine (ZDV) and zalcitabine (ddC) was evaluated in HIV-infected subjects with CD4+ cell counts between 300 and 500 cells/ml and no more than 14 weeks of prior antiretroviral therapy. A total of 256 subjects enrolled in an open-label, randomized controlled trial. Subjects were randomized equally into treatment groups. All subjects received ZDV and ddC, while half also receive IFN-alpha (3 MU subcutaneously every 24 hr). At 48 weeks the median average area under the curve minus baseline (AAUCMB) for plasma HIV-1 RNA for the two-drug group was -0.68 versus -0.75 log10 copies/ml for the IFN-alpha group (p = 0.046). Mean HIV-1 RNA changes from baseline to 48 weeks for these groups were -0.65 and -1.12 log10 copies/ml, respectively (p = 0.010). The median AAUCMB for CD4+ cell count for the two-drug group was 28 versus -1 cells/mm3 for the IFN-alpha group (p = 0.011). Neutropenia, anemia, and drug intolerance were more common in the IFN-alpha group. This study demonstrates that IFN-alpha inhibits HIV-1 replication but attenuates the CD4+ cell response to dual therapy with ZDV and ddC.

Magnetic resonance cystography with gadopenetate dimeglumine of a cystic craniopharyngioma in a child - a technical note.

Large cystic craniopharyngiomas can be treated with chemotherapy injected directly into the cyst. Chemotherapy is toxic if it leaks from the cyst into the subarachnoid space. We present a child with a cystic craniopharyngioma following surgical placement of a catheter into the cystic component. Computed tomography following iodinated contrast injection into the cyst was inconclusive in determining the cyst wall integrity. Magnetic resonance following dilute gadopentetate dimeglumine injection into the cyst clearly defined a leak into the subarachnoid space. Coronal imaging was especially helpful. This technique is simple to perform and useful for clinical management.

Impact of respiratory virus infections on persons with chronic underlying conditions.

CONTEXT: While hospitalization rates have declined overall, hospitalizations for acute lower respiratory tract infections have increased steadily since 1980. Development of new approaches for prevention of acute respiratory tract conditions requires studies of the etiologies of infections and quantification of the risk of hospitalization for vulnerable patients. OBJECTIVE: To determine the frequency of specific virus infections associated with acute respiratory tract conditions leading to hospitalization of chronically ill patients. DESIGN: Analysis of viral etiology of patients hospitalized with acute respiratory tract conditions between July 1991 and June 1995. SETTING: Four large clinics and related hospitals serving diverse populations representative of Harris County, Texas. PATIENTS: A total of 1029 patients who were hospitalized for pneumonia, tracheobronchitis, bronchiolitis, croup, exacerbations of asthma or chronic obstructive pulmonary disease, and/or congestive heart failure. MAIN OUTCOME MEASURE: Virus infection, defined by culture, antigen detection, and significant rise in serum antibodies, by underlying condition; hospitalization rates by low- vs middle-income status. RESULTS: Ninety-three percent of patients older than 5 years had a chronic underlying condition; a chronic pulmonary condition was most common. Patients with chronic pulmonary disease from low-income populations were hospitalized at a rate of 398.6 per 10000, almost 8 times higher than the rate for patients from middle-income groups (52.2 per 10000; P<.001). Of the 403 patients (44.4% of adults and 32.3% of children) who submitted convalescent serum specimens for antibody testing, respiratory tract virus infections were detected in 181 (44.9%). Influenza, parainfluenza, and respiratory syncytial virus (RSV) infections accounted for 75% of all virus infections. CONCLUSIONS: Our study suggests that respiratory virus infections commonly trigger serious acute respiratory conditions that result in hospitalization of patients with chronic underlying conditions, highlighting the need for development of effective vaccines for these viruses, especially for parainfluenza and RSV.

Serious waterborne and wilderness infections.

Serious waterborne and wilderness infections are common and usually treatable if diagnosed early. The differential diagnosis for these infections requires a careful and thorough history and physical examination. Common clinical presentations include acute febrile illnesses, altered mental status, diarrhea, or pneumonia. Pathogens causing serious infections include bacteria, fungi, viruses, and protozoa. Epidemiologic help can be obtained from local or state health departments as well as the Centers for Disease Control.