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Biomedical subjects

A J van Vught

Publications and source records attributed to A J van Vught.

At least 19 recordsLinked to original sources
PubMed2003

[Fulminating pneumococcal septicemia in a 2 year old child with sickle cell anemia].

A 2-year-old boy known with homozygous sickle cell anaemia became acutely ill at home. Despite intensive care, he died a few hours later due to pneumococcal septicaemia. In young children with homozygous sickle cell anaemia, spleen function is already severely impaired in childhood due to haemolysis and frequent vaso-occlusive episodes. These children therefore have an elevated susceptibility to severe invasive infections with encapsulated bacteria. Vaccination against pneumococci at-2 years of age, re-vaccination every 3-5 years, and antibiotic prophylaxis until 5 years of age, and thereafter with possible infections, are therefore necessary.

Anemia, Sickle Cell↗
PubMed2003

Dexamethasone for treatment of patients mechanically ventilated for lower respiratory tract infection caused by respiratory syncytial virus.

BACKGROUND: A study was undertaken to evaluate the efficacy of dexamethasone in patients mechanically ventilated for lower respiratory infection caused by respiratory syncytial virus (RSV-LRTI). METHODS: In a multicentre randomised controlled trial patients were randomised to receive either intravenous dexamethasone (0.15 mg/kg 6 hourly for 48 hours) or placebo. End points were the duration of mechanical ventilation, length of stay (LOS) in the pediatric intensive care unit (PICU) and in hospital, and the duration of supplemental oxygen administration. RESULTS: Thirty seven patients received dexamethasone and 45 received placebo. There was no significant difference in any of the end points between the two groups. In a post hoc analysis patients were stratified into those with mild gas exchange anomalies (PaO(2)/FiO(2) >200 mm Hg and/or mean airway pressure </= 10 cm H(2)O, bronchiolitis group) and those with severe gas exchange anomalies (PaO(2)/FiO(2) </=200 mm Hg and mean airway pressure >10 cm H(2)O, pneumonia group). In the 39 patients with bronchiolitis the duration of mechanical ventilation was 4.3 days shorter in the dexamethasone group than in the placebo group (4.9 v 9.2 days, 95% CI -7.8 to -0.8, p=0.02) and the duration of supplemental oxygen was 3.6 days shorter (7.7 v 11.3 days, 95% CI -8.0 to -0.1, p=0.048). No differences in end points were found in the pneumonia group. CONCLUSIONS: Dexamethasone had no beneficial effect in patients mechanically ventilated for RSV-LRTI but was found to have a beneficial effect in patients with bronchiolitis.

Blood Pressure↗
PubMed2002

[Tetanus in a young unvaccinated girl after a fall in the street].

A 4-year-old girl developed tetanus after she had fallen on the street a week before. She had never been vaccinated and despite pressure from the family practitioner, the parents refused to allow her to be given human anti-tetanus immunoglobulin as a matter of principle after the wound had been stitched. Seven days later she was admitted to hospital with trismus and risus sardonicus. Upon initial treatment with human anti-tetanus immunoglobulin and penicillin, and subsequently metronidazole, her clinical condition deteriorated with opisthotonus and life-threatening respiratory insufficiency, upon which she was moved to the intensive-care department where she was intubated and mechanically ventilated for two weeks. Finally she made a complete clinical recovery. Thanks to the extensive national vaccination program, tetanus has become a rare disease in the Netherlands. However, the very serious course and possible fatal outcome warrant a keen attitude and adequate treatment.

Accidental Falls↗
PubMed2001

Reduction of oscillatory pressure along the endotracheal tube is indicative for maximal respiratory compliance during high-frequency oscillatory ventilation: a mathematical model study.

We hypothesized that during high-frequency oscillatory ventilation (HFOV), a reduction of peak-to-peak oscillatory pressure along the endotracheal tube is maximal when respiratory system compliance is maximal. We made a mathematical model of the endotracheal tube and the respiratory system of a neonate suffering from idiopathic respiratory distress syndrome (IRDS). The model consisted of linear viscous and inertive elements, a non-linear endotracheal tube resistance, and a non-linear compliance allowing for alveolar recruitment and overdistention. Respiratory compliance was maximal at the transition between maximal recruitment and minimal overdistention. A new variable, the oscillatory pressure ratio (OPR), was defined as the ratio between peak-to-peak oscillatory pressures at the distal end and the proximal opening of the endotracheal tube, respectively. The respiratory variables of four patients were fed into the model, and the relationship between respiratory system compliance and OPR was determined. OPR decreased as compliance increased, except for very low compliances below where 0.08 mL. cm H2O(-1), and OPR increased with increasing compliance. The relationship between mean airway pressure P(aw) and OPR revealed that the minimal OPR (range, 0.37-0.78) and maximal respiratory compliance coincided at the same P(aw). However, the relationship did depend on oscillation frequency, applied oscillatory pressure, and endotracheal tube resistance, parameters that may change during clinical application of HFOV. When 81 permutations of nominal and extreme respiratory variables were used in the model, the minimum OPR (0.60 +/- 0.23) and maximum compliance coincided in all cases. These model experiments support our hypothesis. The results indicate that the OPR may be a useful index to optimize lung expansion, where lung recruitment is maximal and overdistention minimal. In vivo tests will be needed to reveal the feasibility and reliability of such an index for biomedical and clinical application.

Airway Resistance↗
PubMed2001

Once-daily versus multiple-daily gentamicin in infants and children.

In this prospective randomized trial, the efficacy and safety of once-daily administration of gentamicin were compared with multiple-daily administration in infants and children. In addition, pharmacokinetic variables were calculated. Gentamicin therapy was started at a dose of 5 mg/kg per day under individual dose or dosage interval adjustments to achieve target levels. Fifty-two infants and children aged 1 month (postterm) to 16 years were enrolled. The duration of fever from the start of therapy, the percentage decline of C-reactive protein (CRP) on day 3 of treatment, and the clinical outcome were used as efficacy parameters. Nephrotoxicity was evaluated using creatinine serum levels. Basic characteristics in both groups were comparable. A good clinical response was observed in both groups. Fever may have resolved faster with multiple-daily administration, but this was not statistically significant. The percentage of decline of CRP was also comparable in both groups. Nephrotoxicity occurred in six patients, three per group. Many patients were too ill or too young to perform hearing tests, but no clinical signs of ototoxicity were observed. Mean doses of 6.8 mg/kg per day (multiple-daily administration) and 7.3 mg/kg per day (once-daily administration) were necessary to meet the target gentamicin levels. Triple-daily doses had to be reduced to a twice-daily regimen in 17 of 26 children. Dose and dosage interval adaptations can be performed by Bayesian forecasting using a one-compartment model with one set of K(e) and V(d) parameters. The authors consider both regimens equally effective, with a comparable incidence of nephrotoxicity. A starting dose of 6.5 mg/kg once daily is advised.

Adolescent↗
PubMed2000

Monocyte interleukin-12 production is inversely related to duration of respiratory failure in respiratory syncytial virus bronchiolitis.

The correlation of clinical and immunological parameters with the duration of respiratory failure was investigated to identify factors determining the clinical outcome of respiratory syncytial virus (RSV) bronchiolitis necessitating mechanical ventilation. At initiation of mechanical ventilation in 30 patients with RSV, production of interleukin (IL)-12 and IL-10 was measured in 48-h peripheral blood cell cultures that were stimulated with lipopolysaccharide and interferon-gamma. The ventilation index (VI)-an indicator of respiratory dysfunction that includes partial pressure of arterial CO2, peak airway pressure, and respiratory rate-correlated with the duration of mechanical ventilation (r=.47; P=.013). Age was not associated with the duration of mechanical ventilation. A highly significant inverse correlation was found between the duration of mechanical ventilation and the production of IL-12 at admission (r=-.62; P<.001). This correlation was independent of VI. No correlation was found between IL-10 production and the duration of mechanical ventilation. It is hypothesized that low monocyte IL-12 response during initial RSV infection adversely affects clinical outcome of patients with severe RSV bronchiolitis.

Bronchiolitis↗
PubMed2000

Status asthmaticus treated by high-frequency oscillatory ventilation.

We present a 2.5-year-old girl in severe asthma crisis who clinically deteriorated on conventional mechanical ventilation, but was successfully ventilated with high-frequency oscillatory ventilation (HFOV). Although HFOV is accepted as a technique for managing pediatric respiratory failure, its use in obstructive airway disease is generally thought to be contraindicated because of the risk of dynamic air-trapping. However, we suggest that obstructive airway disease can safely be managed with HFOV, provided certain conditions are met. These include the application of sufficiently high mean airway pressures to open and stent the airways ("an open airway strategy"), lower frequencies to overcome the greater attenuation of the oscillatory waves in the narrowed airways, permissive hypercapnia to enable reducing pressure swings as much as possible, longer expiratory times, and muscle paralysis to avoid spontaneous breathing.

Child, Preschool↗
PubMed2000

Pediatric risk of mortality (PRISM) score in meningococcal disease.

UNLABELLED: To assess the pediatric risk of mortality (PRISM) score as a prognostic scoring system in severe meningococcal disease, the files of 53 consecutive patients admitted to a tertiary pediatric intensive care with a clinical diagnosis of meningococcal disease and positive cultures from blood and/or cerebrospinal fluid were analysed. PRISM-score-based expected mortality was compared with observed mortality. Expected mortality in the whole study population was 29% while observed mortality was 19% (P<0.05). The highest expected and observed mortality was found in septicaemic patients without (documented) meningitis, while meningitis patients without septicaemia had the lowest mortality. All patients with a mortality risk below 18.3% (n = 29) survived whereas all those with a mortality risk of 65% or higher (n = 7) died. Of the 17 patients with a mortality risk between 18.3% and 63.9%, 14 survived and 3 died. The area under the receiver-operating characteristic (ROC) curve was 0.94, which is at least comparable with the best-performing meningococcal-disease-specific scoring systems. CONCLUSION: The PRISM score is a useful generic measure of severity of illness in meningococcal disease and can be used to determine the effectiveness of different treatment strategies.

Adolescent↗
PubMed2000

High-frequency oscillatory ventilation in pediatric patients.

BACKGROUND: High-frequency oscillatory ventilation (HFOV) is a ventilatory mode using small tidal volumes with low phasic pressures at supraphysiological frequencies. Beyond the neonatal period there are distinct lung diseases for which HFOV is used. Data of 35 children who deteriorated on conventional ventilation were retrospectively analysed in two tertiary pediatric intensive care units. METHODS: Depending on the underlying pulmonary pathophysiology, three strategies were employed. First, the 'open-lung' strategy designed to rapidly recruit and maintain optimal lung volume in DAD (n=27) and pulmonary hemorrhage (n=5). Second, the 'low-volume' strategy in persistent air leak (n=1) where, after an initial identical approach, mean airway pressure (MAP) is reduced until the air leak ceases. Third, the 'open-airway' strategy in obstructive airway disease (n=5) where MAP is used to recruit and stent the airways. RESULTS: Seven patients died, two due to respiratory failure. Three patients developed an air leak. Nine patients developed chronic lung disease. There was a significant decrease of the oxygenation index (OI) in the survivors. In the two patients who died of respiratory failure, the OI increased. CONCLUSION: If certain conditions are met, HFOV appears a safe and effective mode of ventilation in pediatric respiratory failure.

Adolescent↗
PubMed1999

Prophylaxis against respiratory syncytial virus in premature infants.

Postconceptional age was studied in 33 mechanically ventilated preterm infants with respiratory syncytial virus (RSV) bronchiolitis. Preterm infants without chronic lung disease had an increased risk of severe RSV infection until a postconceptional age of 44 weeks.

Bronchiolitis, Viral↗
PubMed1999

[Lung damage due to mechanical ventilation].

Mechanical ventilation in both children and adults is still associated with development of lung injury, both short term and long term. In particular, ventilation with high tidal volumes and low positive end-expiratory pressures (PEEP) contributes significantly to development of lung injury. Suggested preventive measures consist of limiting peak inflation pressures, preventing high tidal volumes, and applying high PEEP to prevent alveolar collapse. Recent studies have demonstrated that mechanical ventilation, via stretch of lung tissue, results in an inflammatory reaction in the lungs. This is known as biotrauma. The degree of inflammation depends on the ventilator settings and mode of ventilation. This inflammatory reaction may not be limited to the lungs but, via inflammatory mediators, may cause multiple organ dysfunction as well. Future research needs to be concentrated on how to modify this ventilator induced inflammatory reaction in order to prevent lung injury as well as systemic injury.

Acute-Phase Reaction↗
PubMed1999

Pro- and anti-inflammatory cytokine patterns during and after cardiac surgery in young children.

UNLABELLED: The systemic inflammatory response that occurs after cardiopulmonary bypass shows many changes similar to those seen in sepsis. The mechanisms for these changes have been attributed to cellular and humoral activation, such as increased secretion of cytokines and complement. The aim of our study was to investigate the cytokine pattern of pro- and anti-inflammatory cytokines in young children during and after bypass surgery. Nineteen children undergoing either septal defect correction (n = 12), or more complex surgery (n = 7), were prospectively included in this study. There were significant higher pre-operative levels of circulating cytokines in the latter group. Cardiopulmonary bypass surgery induced in both groups a rise in circulating cytokine levels and a sharp decline in the capacity of the leucocytes to secrete interleukines-6 and -8 in response to ex vivo stimulation with lipopolysaccharide. Ex vivo production of interleukine-1 receptor antagonist was slightly attenuated by the procedure. CONCLUSIONS: The downregulation of ex vivo pro- and, to some extent, anti-inflammatory cytokine production may be a reflection of a cellular stress response, induced by anaesthesia, cardiopulmonary bypass and surgery.

Anti-Inflammatory Agents↗
PubMed1999

Circumstances of dying in hospitalized children.

UNLABELLED: Conditions of dying in a tertiary children's hospital were assessed in a retrospective cohort study. Non-survivors, excluding newborns and emergency room patients, were allocated to four groups: brain death (BD), failed cardiopulmonary resuscitation (failed CPR), death following a do-not-resuscitate (DNR) order and death following withholding or withdrawal of therapy (W/W). In a 4-year period 190 (1.3%) of 14,903 admitted patients died. Of these 134 (71%) died on the paediatric intensive care unit, 42 (22%) on the ward and 14 (7%) in the operating room. W/W was found in 75 (39%), failed CPR in 57 (30%), BD in 32 (17%), and death following a DNR order in 26 (14%). Justifications for restrictions of treatment (W/W or DNR) were imminent death in 41 (41%), lack of future relational potential in 13 (13%) and excessive burden of disease in 47 (47%). In non-survivors analgesics and sedatives were frequently used to relieve suffering in the terminal phase. General principles for the approach of terminally ill children in whom death may become an option instead of a fate are discussed. CONCLUSION: In the majority of children dying in hospital, death occurred following restrictions of life-sustaining treatment, comprising do-not-resuscitate or other forms of withholding or withdrawal of therapy.

Adolescent↗
PubMed1998

[Pertussis in young infants].

Four infants, three girls aged 4 weeks, 2.5 months and 3 months, and a boy aged 2 months, were hospitalized because of severe respiratory distress. Apnoea spells with bradycardia and hypoxia were seen in two of the patients, one showing convulsions as well, and bronchopneumonia in the other two, of whom one eventually died. All suffered from pertussis. During outbreaks of pertussis, infants less than 6 months of age are at highest risk for severe disease. In this age group, however, the clinical signs of pertussis are often atypical. Classical symptoms such as paroxysms of cough and loud whoops may be absent while feeding problems, apnoea, cyanosis and bradycardia may be present. For infants younger than 6 months with signs indicating pertussis hospitalization is indicated. In the current vaccination schedule in the Netherlands infants are vaccinated at 3, 4, 5 and 11 months of age. Starting in 1999 the first vaccination will be administered at the age of 2 months.

Anti-Bacterial Agents↗
PubMed1997

Bench test assessment of dosage accuracy and measurement inaccuracy in nitric oxide inhalational therapy during high frequency oscillatory ventilation.

OBJECTIVE: The objective of this study is to determine the accuracy and precision of chemiluminescence and electrochemical nitric oxide (NO) measurements and accuracy of NO dosage with electronic mass flow controllers (MFC) versus rotameters during NO inhalational therapy. METHODS: NO flow was delivered to a high frequency oscillator and mixed with ventilator flow. NO and NO2 concentrations were measured simultaneously with a standard chemiluminescence analyzer and a modified electrochemical analyzer. Dosage accuracy was assessed with gas flows adjusted with either MFC's or rotameters. Accuracy of both analyzers was validated with both NO and ventilator flow regulated with a MFC. RESULTS: In dry air, without pulsatile pressure, MFC controlled NO and ventilator flow resulted in an accuracy expressed as the ratio of calculated concentration to measured concentration (RCM) of 0.995 (CI: 0.983-0.988) when measured with chemiluminescence. When the ventilator rotameter was used instead of a MFC, RCM was 0.856 (CI: 0.835-0.877). With a rotameter for both NO and ventilator flow, RCM increased to 1.175 (CI: 0.793-1.740) with an increase of confidence interval limits. Chemiluminescence was sensitive to humidification of the ventilatory gases (p < 0.05), slightly sensitive to the addition of oxygen and to pulsatile pressure (not significant). RCM obtained with the modified electrochemical analyzer was in close agreement with chemiluminescence RCM, although 95% CI were wider with electrochemical analysis. CONCLUSIONS: During high frequency oscillatory ventilation (HFOV), standard rotameter flow control of both NO and ventilator flow results in unpredictable NO concentrations that would be clinically unacceptable. When one MFC was used for NO flow control, with ventilator flow controlled with a rotameter, this resulted in moderate dosage accuracy. To achieve a still higher accuracy, MFC flow control for both NO and ventilator flow is indicated. During HFOV, standard chemiluminescence analyzers cannot be considered to be the gold standard for determination of the NO concentration delivered. Measurement of NO concentration may not be mandatory for determination of inhaled NO dose during HFOV, but may be used to monitor for unsafe or unwanted events.

Administration, Inhalation↗