Congenital posterolateral diaphragmatic hernia : pathophysiological studies and clinical picture

Congenital diaphragmatic hernias are classified according to the location of the defect: posterolateral hernia with or without a sac (Bochdalek-type), parasternal hernia through the foramen of Morgagni, central hernia, and diaphragmatic eventration. The so-called hiatal hernia has a different pathophysiology and a different clinical presentation. Posterolateral defects account for 85% of congenital diaphragmatic herniasY Left-sided posterolateral defects occur eight times more frequently than right-sided defects in the neonatal period. Bilateral defects are rare and estimated at 3 to 5%.3 Children at the highest risk of dying are they who are symptomatic in the delivery room or within six hours after birth.' The mortality rate reported in this group ranges from 40 to 50%." Conversely, those who do not develop respiratory failure in the first 24 hours of life have an almost 100% chance of survival. In contrast to other major congenital anomalies the mortality due to congenital posterolateral diaphragmatic hernia remains high despite improvements in neonatal intensive care and pediatric surgery.'~ The main reason is that pulmonary hypoplasia and pulmonary hypertension form the pathophysiological basis for the clinical picture of respiratory distress and right-to-left shunting that frustrates so many clinicians responsible for newborns with a diaphragmatic defect. This thesis presents the research into clinical aspects of congenital posterolateral diaphragmatic hernia related to pulmonary hypoplasia and pulmonary hypertension; the pathophysiological background of these disorders was studied in an animal model. The clinical studies were all carried out in the Pediatric Surgical Intensive Care Unit of the Sophia Children's Hospital. The animal model was developed by TenBrinck and coworkers in the Laboratory of Experimental Surgery of the Erasmus University in Rotterdam.' In this model congenital diaphragmatic hernia is induced in fetal rats by means of administering a single dose of Nitrofen (2,4-dichlorophenylp- nitrophenyl ether) on the lOth day of gestation. The model interferes with lung development in an early stage, thus providing the opportunity to study several aspects of lung development in relation to both ventilatory capacity and pulmonary vascular reactivity. The results of the conducted studies, as they have been reported and discussed in papers either published or accepted by international journals, form the core of this thesis. These papers are preceded by a review of the literature focussed on historical aspects, clinical picture and normal and abnormal lung development. They are followed by a concluding chapter in which changing concepts concerning pathogenesis and treatment are discusse

Biphasic positive airway pressure ventilation (PeV+) in children

BACKGROUND: Biphasic positive airway pressure (BIPAP) (also known as PeV+) is a mode of ventilation with cycling variations between two continuous positive airway pressure levels. In adults this mode of ventilation is effective and is being accepted with a decrease in need for sedatives because of the ability to breathe spontaneously during the entire breathing cycle. We studied the use of BIPAP in infants and children. METHODS: We randomized 18 patients with respiratory failure for ventilation with either BIPAP (n = 11) or assisted spontaneous breathing (ASB) (n = 7) on Evita 4. Lorazepam and, if necessary, morphine were used as sedatives and adjusted in accordance with the Comfort scale. We compared number of randomized mode failure, duration and complications of ventilation and number and dosages of sedatives administered. RESULTS: No differences in patient characteristics, ventilatory parameters, complications of ventilation or use of sedatives were noted. Ten out of eleven patients that we intended to ventilate with BIPAP were successfully ventilated with BIPAP. Four out of seven patients that we intended to ventilate with ASB could not be ventilated adequately with ASB but were successfully crossed over to BIPAP without the need for further sedatives. CONCLUSIONS: BIPAP is an effective, safe and easy to use mode of ventilation in infants and children

Flumes and weirs

Presented at the 2002 USCID/EWRI conference, Energy, climate, environment and water - issues and opportunities for irrigation and drainage on July 9-12 in San Luis Obispo, California.Includes bibliographical references.Long-throated flumes and broad-crested weirs provide a practical, low-cost, flexible means of measuring open-channel flows in new and existing irrigation systems and have distinct advantages over other flume and weir devices. Application of these flumes and weirs has been greatly facilitated by the 1999 release of the WinFlume software used to design and calibrate these structures, and the recent publication of Water Measurement with Flumes and Weirs, a text providing comprehensive information on design, calibration, construction, and operation issues. The primary advantages of these flumes and weirs are that they can be custom-designed to satisfy unique operational and site requirements, and they can be computer calibrated without the need for laboratory testing. In addition, these devices are easily and economically constructed, and a number of commercially built, pre-calibrated devices are available. This paper and accompanying poster describe the use of the WinFlume software and present examples to illustrate application to a range of situations, including various flow rates, channel types, and construction techniques

Cardiopulmonary resuscitation in paediatric intensive care patients

Abstract To identify the success of cardiopulmonary resuscitation in the paediatric ICU patient we undertook a retrospective study in an 11-bed medical and a 14-bed surgical paediatric ICU over a 32-month period. Thirtyfour patients suffered an arrest in the ICU. Only 4 patients could be resuscitated successfully; 1 died after 24 h. Of the 3 long-term survivors 1 suffered from severe neurologic sequelae. All patients were in CCS classes III or IV. All but 3 patients had PSI scores >8. The decision to resuscitate or to withhold therapy in individual patients who are deteriorating in the course of a critical, preceding illness should not be based on the risk index of these scoring systems. Both medical and ethical considerations should be guidelines in the process of decision-making

Het effect van een sensitivering door een pretest op de verwerving van natuurwetenschappelijke begrippen

De verminderde beschikbaarheid van vakdocenten in het Nederlandse voortgezet onderwijs maakt het gewenst te zoeken naar effectiever onderwijs voor het leren van begrippen in bètavakken. Vanuit de schematheorie en onderzoek naar voorkennistoetsing lijkt het mogelijk om voorafgaand aan daadwerkelijke begripsverwerving relevante, al bestaande begripsnetwerken te activeren met een test. In een experimentele onderwijsopzet is nagegaan of deze sensitivering door een pretest in combinatie met een interactief digitaal systeem de effectiviteit van het onderwijs vergroot. De inhoud van het experimentele onderwijs betrof een oriëntatie op concepten op het grensvlak van de exacte vakken (inclusief informatica). De effecten van deze experimentele onderwijsopzet werden onderzocht in een uitgebreid Solomon Four onderzoeksdesign. Daarin werd het al dan niet operationeel maken van begrippen al dan niet gecombineerd met pretesten waarin zowel kort-antwoordvragen als meerkeuzevragen voorkwamen. In afzonderlijke experimenten werden betrouwbaarheid en equivalentie van de verschillende testen vastgesteld. De resultaten laten een hoge onderwijswinst zien, het meest na het toepassen van pretesten, maar ook zonder pretesten werden forse winsten gemeten. Er werd een significante interactie tussen pretest en de hoofdtreatment vastgesteld. Er werd geen verschil in pretesteffect van de twee vraagtypen geconstateerd. Het toepassen van een pretest zonder het operationeel maken van de begrippen had geen effect

New Tools for Systematic Evaluation of Teaching Qualities of Medical Faculty: Results of an Ongoing Multi-Center Survey

Background: Tools for the evaluation, improvement and promotion of the teaching excellence of faculty remain elusive in residency settings. This study investigates (i) the reliability and validity of the data yielded by using two new instruments for evaluating the teaching qualities of medical faculty, (ii) the instruments' potential for differentiating between faculty, and (iii) the number of residents' evaluations needed per faculty to reliably use the instruments. Methods and Materials: Multicenter cross-sectional survey among 546 residents and 629 medical faculty representing 29 medical (non-surgical) specialty training programs in the Netherlands. Two instruments-one completed by residents and one by faculty-for measuring teaching qualities of faculty were developed. Statistical analyses included factor analysis, reliability and validity exploration using standard psychometric methods, calculation of the numbers of residents' evaluations needed per faculty to achieve reliable assessments and variance components and threshold analyses. Results: A total of 403 (73.8%) residents completed 3575 evaluations of 570 medical faculty while 494 (78.5%) faculty self-evaluated. In both instruments five composite-scales of faculty teaching qualities were detected with high internal consistency and reliability: learning climate (Cronbach's alpha of 0.85 for residents' instrument, 0.71 for self-evaluation instrument, professional attitude and behavior (0.84/0.75), communication of goals (0.90/0.84), evaluation of residents (0.91/0.81), and feedback (0.91/0.85). Faculty tended to evaluate themselves higher than did the residents. Up to a third of the total variance in various teaching qualities can be attributed to between-faculty differences. Some seven residents' evaluations per faculty are needed for assessments to attain a reliability level of 0.90. Conclusions: The instruments for evaluating teaching qualities of medical faculty appear to yield reliable and valid data. They are feasible for use in medical residencies, can detect between-faculty differences and supply potentially useful information for improving graduate medical educatio