Event-by-event fluctuations of azimuthal particle anisotropy in Au+Au collisions at square root(sNN) = 200 GeV.

This Letter presents the first measurement of event-by-event fluctuations of the elliptic flow parameter v(2) in Au+Au collisions at square root(s(NN))=200 GeV as a function of collision centrality. The relative nonstatistical fluctuations of the v(2) parameter are found to be approximately 40%. The results, including contributions from event-by-event elliptic flow fluctuations and from azimuthal correlations that are unrelated to the reaction plane (nonflow correlations), establish an upper limit on the magnitude of underlying elliptic flow fluctuations. This limit is consistent with predictions based on spatial fluctuations of the participating nucleons in the initial nuclear overlap region. These results provide important constraints on models of the initial state and hydrodynamic evolution of relativistic heavy ion collisions.

High transverse momentum triggered correlations over a large pseudorapidity acceptance in Au + Au collisions at square root(s(NN)) = 200 GeV.

A measurement of two-particle correlations with a high transverse momentum trigger particle (p(T)(trig) > 2.5 GeV/c) is presented for Au+Au collisions at square root(s(NN)) = 200 GeV over the uniquely broad longitudinal acceptance of the PHOBOS detector (-4 < Delta eta < 2). A broadening of the away-side azimuthal correlation compared to elementary collisions is observed at all Delta eta. As in p+p collisions, the near side is characterized by a peak of correlated partners at small angle relative to the trigger particle. However, in central Au+Au collisions an additional correlation extended in Delta eta and known as the "ridge" is found to reach at least |Delta eta| approximately = 4. The ridge yield is largely independent of Delta eta over the measured range, and it decreases towards more peripheral collisions. For the chosen (p(T)(trig) cut, the ridge yield is consistent with zero for events with less than roughly 100 participating nucleons.

Paraldehyde therapy in childhood status epilepticus.

Intravenous (IV) diazepam or phenobarbital is generally accepted as the initial treatment of choice for status epilepticus in children. The risk of severe respiratory depression with either drug is a major problem, particularly in emergency centers that do not have appropriate equipment or personnel for rapid endotracheal intubation of infants. While some pediatric centers are not reluctant to recommend paraldehyde for secondary therapy in status epilepticus, most texts and publications recommend it only as a last resort because of reported complications. We investigated the benefits and complications from varied dosing regimens in 16 trials. The results indicated no significant complications in patients who did not receive an initial IV bolus. Even though treatment with phenobarbital or diazepam and phenytoin sodium had failed, 37% had a good therapeutic response.

Radionuclide cerebral perfusion scintigraphy in determination of brain death in children.

We evaluated a radionuclide scintigraphic technique for imaging relative cerebral perfusion in 18 children who had no evidence of cortical and brainstem function. Patients without scintigraphic evidence of cerebral perfusion all later met criteria for diagnosis of brain death. Patients who failed to satisfy brain-death criteria had persistent scintigraphic evidence of cerebral perfusion. Seven patients with normal scintigraphic studies were being treated with barbiturates and hypothermia at levels that attenuated or completely suppressed EEG activity. Four patients without scintigraphic evidence of cerebral perfusion had mean arterial pressures (MAP) higher than (54.8 +/- 7.6 torr) intracranial pressures (ICP) at the time of scintigraphic study, suggesting that ICP in excess of MAP is not the sole explanation for the absence of cerebral perfusion. Radionuclide cerebral perfusion scintigraphy (RCPS) is a rapid, portable, accurate test that appears to be useful in the diagnosis of brain death in the pediatric population.

Role of flexible bronchoscopy and bronchoalveolar lavage in the diagnosis of pediatric acquired immunodeficiency syndrome-related pulmonary disease.

Flexible fiberoptic bronchoscopy with bronchoalveolar lavage was performed in 16 pediatric patients with the acquired immunodeficiency syndrome (AIDS) and deterioration in pulmonary function suggestive of opportunistic infection. In 62% of the patients Pneumocystis carinii was identified. Culture results showed a pure growth of Pseudomonas aeruginosa for one patient in addition to the Pneumocystis carinii. Bronchoscopy with lavage was well tolerated, with few complications even among patients with significant tachypnea and hypoxia. Because of its relative safety and effectiveness, this procedure should be considered the first invasive measurement used for evaluation of parenchymal lung disease in this population of patients.

Respiratory failure in children with acquired immunodeficiency syndrome and acquired immunodeficiency syndrome-related complex.

Acute respiratory failure has a high mortality in patients with acquired immunodeficiency syndrome (AIDS). This study was undertaken to determine the etiology of acute respiratory failure and the outcome of children with AIDS and AIDS-related complex. Records of 31 children with AIDS or AIDS-related complex admitted to the pediatric intensive care unit for acute respiratory failure throughout a 46-month period were reviewed. Acute respiratory failure was due to Pneumocystis carinii pneumonia in 13, cytomegalovirus pneumonia in six, bacterial pneumonia in five, severe bacterial sepsis in four, Candida pneumonia in two, and a giant cell pneumonia in one patient. In addition, 11/19 patients with acute respiratory failure due to P carinii pneumonia or cytomegalovirus had superinfections with bacteria or Candida. Of the total of 19 primary and secondary bacterial infections, Pseudomonas aeruginosa was responsible in ten and Klebsiella pneumoniae in three children. Five children (16%) survived until pediatric intensive care unit discharge; three died within 6 months. The causes of acute respiratory failure were not significantly different in survivor and nonsurvivor groups. It is concluded that, in addition to P carinii pneumonia and cytomegalovirus pneumonia, bacterial infections (especially due to Pseudomonas and other Gram-negative organisms) are important causes of respiratory failure. The high mortality and grim ultimate prognosis seen may have implications for pediatricians attempting to identify the proper limits of medical intervention for this group of patients.

Surveillance study of pediatric patients receiving respiratory therapy, using the Bain circuit system.

The Bain circuit, which has been used previously for anesthesia, was adopted for long-term mechanical ventilation for infants and children in a pediatric intensive care unit. When this ventilation system is used, humidifier temperatures must be kept at temperatures significantly lower than the recommended 50 degrees C to avoid excessive airway temperatures and thermal injury. Routine infection control measures such as daily changing of respiratory therapy equipment and the use of sterile water in Cascade humidifiers were enforced. It was demonstrated that the use of the Bain circuit with a Cascade humidifier kept at a temperature of 36.9 degrees +/- 1.9 degrees C was not associated with nosocomial infection of the lower respiratory tract.

Brain death: considerations for pediatrics.

During the past 15 years, the concept that irreversible cessation of brain function is synonymous with death of the individual has become generally accepted, both by medical professionals and by society at large. We review the rationale and evidence supporting this principle, with special attention to pediatric applications. The use and reliability of various confirmatory tests are discussed, and specific brain death criteria are suggested.

Control of infection and techniques of isolation in the pediatric intensive care unit.

The control of nosocomial infection in a pediatric intensive care unit is important not only because of the serious nature of the patient's condition, but also because of the greater staff-patient contact and inevitable crowding of patients, staff, and equipment. In order to control the spread of nosocomial infection, the modes of transmission and the principles of infection control must be understood. Each patient with an infectious disease must be considered to be a potential source of nosocomial disease, and measures of infection control must be individualized for the infectious disease and for the level of intensive care required. The infection control committee of the hospital is an excellent source of advice in formulating care plans. Although compromises will inevitable be made between the ideals of infection control and intensive care needs, certain principles must be followed, the most important of which is proper handwashing between contacts and with patients.

System size, energy, and centrality dependence of pseudorapidity distributions of charged particles in relativistic heavy-ion collisions.

We present the first measurements of the pseudorapidity distribution of primary charged particles in Cu+Cu collisions as a function of collision centrality and energy, sqrt[s_{NN}]=22.4, 62.4, and 200 GeV, over a wide range of pseudorapidity, using the PHOBOS detector. A comparison of Cu+Cu and Au+Au results shows that the total number of produced charged particles and the rough shape (height and width) of the pseudorapidity distributions are determined by the number of nucleon participants. More detailed studies reveal that a more precise matching of the shape of the Cu+Cu and Au+Au pseudorapidity distributions over the full range of pseudorapidity occurs for the same N{part}/2A rather than the same N_{part}. In other words, it is the collision geometry rather than just the number of nucleon participants that drives the detailed shape of the pseudorapidity distribution and its centrality dependence at RHIC energies.

System size, energy, pseudorapidity, and centrality dependence of elliptic flow.

This Letter presents measurements of the elliptic flow of charged particles as a function of pseudorapidity and centrality from Cu-Cu collisions at 62.4 and 200 GeV using the PHOBOS detector at the Relativistic Heavy Ion Collider. The elliptic flow in Cu-Cu collisions is found to be significant even for the most central events. For comparison with the Au-Au results, it is found that the detailed way in which the collision geometry (eccentricity) is estimated is of critical importance when scaling out system-size effects. A new form of eccentricity, called the participant eccentricity, is introduced which yields a scaled elliptic flow in the Cu-Cu system that has the same relative magnitude and qualitative features as that in the Au-Au system.

Energy dependence of directed flow over a wide range of pseudorapidity in Au + Au collisions at the BNL Relativistic Heavy Ion Collider.

We report on measurements of directed flow as a function of pseudorapidity in Au + Au collisions at energies of square root of SNN = 19.6, 62.4, 130 and 200 GeV as measured by the PHOBOS detector at the BNL Relativistic Heavy Ion Collider. These results are particularly valuable because of the extensive, continuous pseudorapidity coverage of the PHOBOS detector. There is no significant indication of structure near midrapidity and the data surprisingly exhibit extended longitudinal scaling similar to that seen for elliptic flow and charged particle pseudorapidity density.

System size and centrality dependence of charged hadron transverse momentum spectra in Au + Au and Cu + Cu collisions at square root of SNN = 62.4 and 200 GeV.

We present transverse momentum distributions of charged hadrons produced in Cu + Cu collisions at square root of SNN = 62.4 and 200 GeV. The spectra are measured for transverse momenta of 0.25 < pT < 5.0 GeV/c at square root of SNN = 62.4 GeV and 0.25 < pT < 7.0 GeV/c at square root of SNN = 200 GeV, in a pseudorapidity range of 0.2 < eta < 1.4. The nuclear modification factor R(AA) is calculated relative to p + p data at both collision energies as a function of collision centrality. At a given collision energy and fractional cross section, R(AA) is observed to be systematically larger in Cu + Cu collisions compared to Au + Au. However, for the same number of participating nucleons, R(AA) is essentially the same in both systems over the measured range of pT, in spite of the significantly different geometries of the Cu + Cu and Au + Au systems.

Centrality dependence of charged hadron transverse momentum spectra in Au+Au collisions from sqrt[s(NN)]=62.4 to 200 GeV.

We have measured transverse momentum distributions of charged hadrons produced in Au+Au collisions at sqrt[s(NN)]=62.4 GeV. The spectra are presented for transverse momenta 0.25

Energy dependence of elliptic flow over a large pseudorapidity range in Au+Au collisions at the BNL relativistic heavy ion collider.

This Letter describes the measurement of the energy dependence of elliptic flow for charged particles in Au+Au collisions using the PHOBOS detector at the Relativistic Heavy Ion Collider. Data taken at collision energies of square root of s(NN)=19.6, 62.4, 130, and 200 GeV are shown over a wide range in pseudorapidity. These results, when plotted as a function of eta(')=|eta|-y(beam), scale with approximate linearity throughout eta('), implying no sharp changes in the dynamics of particle production as a function of pseudorapidity or increasing beam energy.

Modified Mapleson D system for long-term mechanical ventilation of infants and children.

The Bain circuit, a modified Mapleson D system, is a lightweight, simple circuit which has been used primarily for anesthesia. This report describes its use for long-term mechanical ventilation for infants and children. The use of this circuit improved warming of inspired gas reducing patient heat loss and, additionally, it was believed to have resulted in increased humidity of the inspired gas. There were no instances of accidental extubation nor were any of the endotracheal tubes blocked by inspissated secretions. Temperatures of the humidifiers had to be lower than conventionally recommended but this did not result in any nosocomial infections. This circuit is an effective and safe circuit to use for long-term mechanical ventilation of children.

Single coronary artery originating from the right pulmonary artery.

An infant with a single coronary artery originating from the right pulmonary artery branch is the subject of this report. He survived to the age of one month possibly because of the association of two ventricular septal defects. While the pulmonary vascular resistance remained high, perfusion of the heart muscle was accomplished due to the pulmonary hypertension. The electrocardiogram did not show typical signs of infarction, but poor left ventricular contractility was observed by echocardiogram. The diagnosis was made postmortem. This specific coronary malformation has not been previously described and needs to be included in the classification of congenital coronary arteries anomalies.

Central nervous system anoxic-ischemic insult in children due to near-drowning.

An analysis of admission and follow-up CT examinations of the brains of 17 children who had nearly drowned (15 of whom were comatose and two of whom were conscious on admission) indicated that a normal initial CT scan is common in the majority of comatose patients, a severe neurologic outcome may develop in spite of a normal initial CT examination, and abnormal initial or follow-up CT findings indicate the strong but not inevitable probability of a severe neurologic outcome. We conclude that when there is no head trauma, an initial CT examination is not necessary. Prediction of the clinical outcome cannot be made on the basis of the initial CT findings.