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Search Results: 1 - 10 of 146168 matches for " Frans B Pl?tz "
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Surfactant therapy and extracorporeal life support
Frans B Pltz
Critical Care , 2005, DOI: 10.1186/cc3933
Abstract: In animal studies using 141Ce-labelled microspheres mixed with the surfactant [2,3], we observed that, following endotracheal administration, this surfactant preparation was distributed inhomogeneously in the lungs. However, significantly improved distribution was achieved when this dose of surfactant (100 mg/kg body weight) was diluted with normal saline to a concentration of 6.25 g/l. In order to apply this dose, intratracheal fluid administration of 16.0 ml/kg body weight was required. Subsequently, we evaluated the effect of large volume fluid installation in lung lavaged rabbits while applying two gas exchange techniques, namely continuous positive pressure ventilation and LFV-ECCO2R [4]. We observed significantly higher arterial oxygen tension in the LFV-ECCO2R group than in the control group in the normocapnic state.Based on these promising findings we further explored weaning possibilities [5]. Four hours after surfactant instillation in lung lavaged rabbits, the inspired fraction of oxygen could be decreased to 40% in a stepwise manner, such that arterial oxygen tension could easily be maintained within the normal range. Extracorporeal flow rates during perfusion ranged from 20 to 35 ml/kg per min and were sufficient to keep the arterial carbon dioxide tension and pH within normal limits. After 4 hours, the lung lavaged rabbits could breathe spontaneously with continuous positive airway pressure and 40% oxygen, and normal blood gas values were maintained. Using LFV-ECCO2R we required flow rates of only 20–35 ml/kg per min and were able to use a small, compact circuit, thereby minimizing the additional adverse effects of an extracorporeal circuit [6,7]. Our findings indicate that barotrauma/volutrauma due to mechanical ventilation and oxygen toxicity due to high fraction of inspired oxygen can be minimized in an animal model of acute severe respiratory failure using combined LFV-ECCO2R and surfactant therapy.I hope that this additional information will stimu
Bench-to-bedside review: Paediatric viral lower respiratory tract disease necessitating mechanical ventilation – should we use exogenous surfactant?
Martin CJ Kneyber, Frans B Pltz, Jan LL Kimpen
Critical Care , 2005, DOI: 10.1186/cc3823
Abstract: Each winter paediatric intensivists are challenged with infants and young children with viral lower respiratory tract disease (LRTD) necessitating mechanical ventilation (MV). In the majority of cases the causative agent is respiratory syncytial virus (RSV), although other viruses such as the parainfluenza virus, human metapneumovirus, adenovirus and influenza virus have also been implicated [1-4]. The number of infants hospitalized with RSV LRTD in the USA annually is currently above 100,000 and still rising [5]. Respiratory failure necessitating MV occurs in 2–16% of previously healthy infants. This percentage may increase to 36% in prematurely born infants or infants with chronic lung disease [6,7]. The duration of MV may be as long as 10 days [8]. The efficacy of corticosteroids or ribavirin in reducing the duration of ventilation and of stay in the paediatric intensive care unit has not been demonstrated [9].From a pathophysiological point of view, the use of exogenous surfactant seems rational. It was initially identified as a complex of lipids and proteins found at the air–liquid interface of the lungs, where its main function is to lower the surface tension [10-12]. A novel function of surfactant came from the emerging evidence that two surfactant proteins (SPs), namely SP-A and SP-D, are involved in the host immune response to various micro-organisms, including viruses [13]. This novel function gained further interest when it was found that these SPs are also expressed outside the lungs.The purpose of this article is to review the role of pulmonary surfactant in the pathogenesis of paediatric viral LRTD necessitating MV, and the potential role of exogenous surfactant as a treatment modality. These functions of surfactant are discussed separately.Pulmonary surfactant is a mixture of approximately 90% lipids and 10% proteins, synthesized within type II alveolar cells and secreted in the alveoli through exocytosis [14]. The best known function of surfactant is
Bench-to-bedside review: Ventilation-induced renal injury through systemic mediator release - just theory or a causal relationship?
Jan Kuiper, Rosanna Vaschetto, Francesco Corte, Frans B Pltz, AB Johan Groeneveld
Critical Care , 2011, DOI: 10.1186/cc10282
Abstract: Acute kidney injury (AKI) is a common problem in critically ill patients and carries significant morbidity and mortality. Based on a recent multinational study, the incidence of AKI is estimated to be 5.7%, with a mortality of 60% [1]. AKI rarely occurs in isolation but usually develops in the context of multiple organ failure. Despite advances in dialysis technology and supportive care, mortality resulting from AKI has remained unchanged over the past years and is as high as 80% when associated with respiratory insufficiency [1,2]. An observational study recently found that 75% of all patients with acute respiratory failure required some form of renal replacement therapy [1].Mechanical ventilation (MV) is an independent risk factor for the development of AKI and can contribute to its development by three proposed mechanisms: blood gas disturbances leading to hypoxemia or hypercapnia and subsequent neurohumoral-mediated effects on renal blood flow during MV; changes in cardiac output, redistribution of intra-renal blood flow and stimulation of hormonal and sympathetic pathways may affect systemic and renal hemodynamics, thereby decreasing renal blood flow; and MV-induced biotrauma, defined as a pulmonary inflammatory reaction to MV with pulmonary mediator release [1,3]. Subsequent spill-over of these mediators into the systemic circulation may contribute to AKI [4].Although various processes play significant roles in the pathophysiology of AKI, this review focuses specifically on the potential role of plasma mediators released as a result of MV in the pathogenesis of AKI. First, we review the current clinical and experimental literature describing mediators that are systemically released during MV and their effect on the kidney. The causality of the relationship between systemically released mediators and AKI will be explored. Second, we identify mediators whose release is attributable to MV and discuss the potential effects of these mediators on the kidney. This wi
Circumstances surrounding dying in the paediatric intensive care unit
Jetske ten Berge, Dana-Anne H de Gast-Bakker, Frans B Pltz
BMC Pediatrics , 2006, DOI: 10.1186/1471-2431-6-22
Abstract: The chart records of all patients less than 18 years of age who died at the PICU between January first 2000 and July first 2005 were retrospectively analyzed. Information regarding sex, age, length of stay, admission, diagnosis, and the way a patient died was registered. Post mortem information regarding natural versus unnatural death, autopsy and donation was obtained. Non-survivors were allocated in five groups: do-not-resuscitate (DNR), withholding and/or withdrawal of therapy (W/W), failed cardiopulmonary resuscitation (failed CPR), brain death (BD), and terminal organ failure (TOF).During the study period 87 (4.4%) of the 1995 admitted patients died. Non-survivors were more often admitted during the day (54%) and the week (68%). W/W was found in 27.6%, TOF in 26.4%, BD in 23.0%, failed CPR in 18.4%, and DNR in 4.6%. Forty-three percent died in the first two days, of which BD (40.5%) and failed CPR (37.8%) were most common. Seventy-five children (86%) died due to a natural cause. Autopsy permission was obtained in 19 of 54 patients (35%). The autopsies confirmed the clinical diagnosis in 11 patients, revealed new information in 5 patients, and in 3 patients the autopsy did not provide additional information. Nine patients were medically suitable for organ donation and 24 patients for tissue donation, whereas consent was only obtained in 2 cases in both groups.We observed that 43% of the patients died within the first two days of admission due to BD and failed CPR, whereas after 4 days most patients died after W/W. Autopsy remains an useful tool to confirm clinical diagnoses or to provide new information. Only a small percentage of the deceased children is suitable for organ donation.Death is inevitable in the paediatric intensive care unit (PICU). Mortality rates differ from 3,8% to 13% in PICUs in North and South America and Europe [1-4]. Nowadays practice of withholding and withdrawal of treatment (W/W) and do not resuscitate (DNR) orders in children are medic
Heliox reduces respiratory system resistance in respiratory syncytial virus induced respiratory failure
Martin CJ Kneyber, Marc van Heerde, Jos WR Twisk, Frans B Pltz, Dick G Markhors
Critical Care , 2009, DOI: 10.1186/cc7880
Abstract: Mechanically ventilated, sedated and paralyzed infants with proven RSV were enrolled within 24 hours after paediatric intensive care unit (PICU)admission. At T = 0, respiratory system mechanics including respiratory system compliance and resistance, and peak expiratory flow rate were measured with the AVEA ventilator. The measurements were repeated at each interval (after 30 minutes of ventilation with heliox, after 30 minutes of ventilation with nitrox and again after 30 minutes of ventilation with heliox). Indices of gas exchange (ventilation and oxygenation index) were calculated at each interval. Air-trapping (defined by relative change in end-expiratory lung volume) was determined by electrical impedance tomography (EIT) at each interval.Thirteen infants were enrolled. In nine, EIT measurements were performed. Mechanical ventilation with heliox significantly decreased respiratory system resistance. This was not accompanied by an improved CO2 elimination, decreased peak expiratory flow rate or decreased end-expiratory lung volume. Importantly, oxygenation remained unaltered throughout the experimental protocol.Respiratory system resistance is significantly decreased by mechanical ventilation with heliox (ISCRTN98152468).Respiratory syncytial virus (RSV) is the most important causative agent of lower respiratory tract disease (LRTD) in infancy [1]. Approximately 100,000 infants are annually admitted with RSV-induced bronchiolitis in the USA, and the number of hospitalizations is increasing [2]. Because of this, RSV-associated disease imposes a major burden on health care resources [3]. There is no effective therapy against RSV available, prevention can only be achieved through passive immunisation using monoclonal antibodies [4]. RSV LRTD is pathophysiologically characterized by sloughed necrotic epithelium, excessive mucus secretion, bronchial mucosal oedema and peribronchial inflammation that contributes to airway obstruction resulting in increased airway resis
Unloading work of breathing during high-frequency oscillatory ventilation: a bench study
Marc van Heerde, Karel Roubik, Vitek Kopelent, Frans B Pltz, Dick G Markhorst
Critical Care , 2006, DOI: 10.1186/cc4968
Abstract: An external gas flow controller (demand-flow system) accommodates the ventilator fresh gas flow during spontaneous breathing simulation. A control algorithm detects breathing effort and regulates the demand-flow valve. The effectiveness of this system has been evaluated in a bench test. The Campbell diagram and pressure time product (PTP) are used to quantify the imposed workload.Using the demand-flow system, imposed WOB is considerably reduced. The demand-flow system reduces inspiratory imposed WOB by 30% to 56% and inspiratory imposed PTP by 38% to 59% compared to continuous fresh gas flow. Expiratory imposed WOB was decreased as well by 12% to 49%. In simulations of shallow to normal breathing for an adult, imposed WOB is 0.5 J l-1 at maximum. Fluctuations in mean airway pressure on account of spontaneous breathing are markedly reduced.The use of the demand-flow system during HFOV results in a reduction of both imposed WOB and fluctuation in mean airway pressure. The level of imposed WOB was reduced to the physiological range of WOB. Potentially, this makes maintenance of spontaneous breathing during HFOV possible and easier in a clinical setting. Early initiation of HFOV seems more possible with this system and the possibility of weaning of patients directly on a high-frequency oscillatory ventilator is not excluded either.Maintenance of spontaneous breathing in mechanically ventilated patients has beneficial effects. Spontaneous breathing augments ventilation perfusion matching and cardiopulmonary function, reduces sedative requirement and shortens intensive care stay [1-5]. High-frequency oscillatory ventilation (HFOV), at least in theory, achieves all goals of lung protective ventilation. It is a useful ventilatory mode for neonatal application [6,7] and is gaining interest in both paediatric and adult intensive care [8-12]. Clinical trials suggest that the use of HFOV at a lower severity threshold of acute respiratory distress syndrome improves outcome [9,13
Venous oxygen measurements in the inferior vena cava in neonates with respiratory failure
Frans B Pltz, Richard A van Lingen, Albert P Bos
Critical Care , 1998, DOI: 10.1186/cc126
Abstract: The study included 22 neonates requiring mechanical ventilation for respiratory insufficiency. The success rate of catheterization of the IVC via the umbilical vein was 81% and there was no catheter-related complications. Fifty paired blood samples were obtained and analyzed while the patients were hemodynamically stable. Linear regression analysis showed a poor correlation between arterial oxygen tension (PaO2) and the arterial-venous oxygen content difference [C(a–v)O2], r = -0.005, and between PaO2 and the fractional oxygen extraction (FOE), r = -0.114. There was also a poor correlation between arterial oxygen saturation (SaO2) and C(a–v)O2, r = -0.057, and between SaO2 and FOE, r =-0.139. The correlations between venous oxygen tension (PvO2) and C(a–v)O2 and between PvO2 and FOE were r = -0.528 and r = 0.592, respectively. There were good correlations between various oxygen saturation (SvO2) and C(a–v)O2, r = -0.634, and between SvO2 FOE, r = -0.712.Venous oxygen measurement in the IVC via an umbilical vein catheter is a simple and safe procedure and provides information about the tissue oxygenation status of critically ill neonates.In neonatal medicine, knowledge about tissue oxygenation is important because hypoxia, as well as hyperoxia, have deleterious effects. For example, unrestricted use of oxygen for low birthweight infants causes retinopathy of prematurity, while extreme lack of oxygen leads to death. Chronic deficiency of oxygen may result in long-term injury to the brain and a subsequent neurodevelopmental handicap. Measurement of oxygenation is, however, often limited to arterial blood, and most clinical decisions regarding oxygen therapy in neonates rely primarily on measurements of arterial oxygen tension (PaO2) and arterial oxygen saturation (SaO2). This approach fails to describe fully the physiological economy of oxygen in terms of supply (systemic oxygen transport), demand (oxygen consumption), or functional reserve (mixed venous oxygen content
Imposed work of breathing during high-frequency oscillatory ventilation: a bench study
Marc van Heerde, Huib R van Genderingen, Tom Leenhoven, Karel Roubik, Frans B Pltz, Dick G Markhorst
Critical Care , 2005, DOI: 10.1186/cc3988
Abstract: A computer-controlled piston-driven test lung was used to simulate a spontaneously breathing patient. The test lung was connected to a high-frequency oscillatory ventilation (HFOV) ventilator by an endotracheal tube. The inspiratory and expiratory airway flows and pressures at various places were sampled. The spontaneous breath rate and volume, tube size and ventilator settings were simulated as representative of the newborn to adult range. The fresh gas flow rate was set at a low and a high level. The imposed WOB was calculated using the Campbell diagram.In the simulations for newborns (assumed body weight 3.5 kg) and infants (assumed body weight 10 kg) the imposed WOB (mean ± standard deviation) was 0.22 ± 0.07 and 0.87 ± 0.25 J/l, respectively. Comparison of the imposed WOB in low and high fresh gas flow rate measurements yielded values of 1.63 ± 0.32 and 0.96 ± 0.24 J/l (P = 0.01) in small children (assumed body weight 25 kg), of 1.81 ± 0.30 and 1.10 ± 0.27 J/l (P < 0.001) in large children (assumed body weight 40 kg), and of 1.95 ± 0.31 and 1.12 ± 0.34 J/l (P < 0.01) in adults (assumed body weight 70 kg). High peak inspiratory flow and low fresh gas flow rate significantly increased the imposed WOB. Mean airway pressure in the breathing circuit decreased dramatically during spontaneous breathing, most markedly at the low fresh gas flow rate. This led to ventilator shut-off when the inspiratory flow exceeded the fresh gas flow.Spontaneous breathing during HFOV resulted in considerable imposed WOB in pediatric and adult simulations, explaining the discomfort seen in those patients breathing spontaneously during HFOV. The level of imposed WOB was lower in the newborn and infant simulations, explaining why these patients tolerate spontaneous breathing during HFOV well. A high fresh gas flow rate reduced the imposed WOB. These findings suggest the need for a demand flow system based on patient need allowing spontaneous breathing during HFOV.Maintenance of spontaneou
High-frequency oscillatory ventilation in children: a single-center experience of 53 cases
Fieke YAM Slee-Wijffels, Klara RM van der Vaart, Jos WR Twisk, Dick G Markhorst, Frans B Pltz
Critical Care , 2005, DOI: 10.1186/cc3520
Abstract: The chart records of 53 consecutively HFOV-treated patients from 1 January 1998 to 1 April 2004 were retrospectively analyzed. The parameters of demographic data, cause of respiratory insufficiency, Pediatric Index of Mortality score, oxygenation index and PaCO2 were recorded and calculated at various time points before and after the start of HFOV, along with patient outcome and cause of death.The overall survival rate was 64%. We observed remarkable differences in outcome depending on the cause of respiratory insufficiency; survival was 56% in patients with diffuse alveolar disease (DAD) and was 88% in patients with small airway disease (SAD). The oxygenation index was significantly higher before and during HFOV in DAD patients than in SAD patients. The PaCO2 prior to HFOV was higher in SAD patients compared with DAD patients and returned to normal values after the initiation of HFOV.HFOV rescue therapy was associated with a high survival percentage in a selected group of children. Patients with DAD primarily had oxygenation failure. Future studies are necessary to evaluate whether the outcome in this group of patients may be improved if HFOV is applied earlier in the course of disease. Patients with SAD primarily had severe hypercapnia and HFOV therapy was very effective in achieving adequate ventilation.High-frequency oscillatory ventilation (HFOV) is, from a theoretical point of view, an ideal method of ventilation to minimize ventilator-associated lung injury. HFOV avoids high peak inspiratory pressures, thus preventing end-inspiratory overdistension, and it avoids repetitive recruitment and de-recruitment of the unstable lung alveoli, thus preventing end-expiratory collapse [1-3]. Despite these factors, HFOV is primarily used as a rescue therapy in pediatric patients with diffuse alveolar disease (DAD), and the reported survival varies between 18% and 67% [4-15].We have used HFOV as a rescue therapy in our pediatric intensive care unit since 1995. In addition,
Mechanical ventilation with high tidal volumes attenuates myocardial dysfunction by decreasing cardiac edema in a rat model of LPS-induced peritonitis
Lonneke Smeding, Frans B Pltz, Regis R Lamberts, Willem J van der Laarse, Martin CJ Kneyber, AB Groeneveld
Respiratory Research , 2012, DOI: 10.1186/1465-9921-13-23
Abstract: Normal rats and intraperitoneal (i.p.) lipopolysaccharide (LPS)-treated rats were ventilated with low (6 ml/kg) and high (19 ml/kg) tidal volumes (Vt) under general anesthesia. Non-ventilated animals served as controls. Mean arterial pressure (MAP), central venous pressure (CVP), cardiac output (CO) and pulmonary plateau pressure (Pplat) were measured. Ex vivo myocardial function was measured in isolated Langendorff-perfused hearts. Cardiac expression of endothelial vascular cell adhesion molecule (VCAM)-1 and edema were measured to evaluate endothelial inflammation and leakage.MAP decreased after LPS-treatment and Vt-dependently, both independent of each other and with interaction. MV Vt-dependently increased CVP and Pplat and decreased CO. LPS-induced peritonitis decreased myocardial function ex vivo but MV attenuated systolic dysfunction Vt-dependently. Cardiac endothelial VCAM-1 expression was increased by LPS treatment independent of MV. Cardiac edema was lowered Vt-dependently by MV, particularly after LPS, and correlated inversely with systolic myocardial function parameters ex vivo.MV attenuated LPS-induced systolic myocardial dysfunction in a Vt-dependent manner. This was associated with a reduction in cardiac edema following a lower transmural coronary venous outflow pressure during LPS-induced coronary inflammation.Septic patients often suffer from myocardial depression and acute lung injury, therefore requiring circulatory and ventilatory support [1]. The cause of the sepsis-induced myocardial dysfunction is multifactorial (for review see [2]) but endothelial activation is considered to be an important pathogenic mechanism [3]. Upon exposure to lipopolysaccharide (LPS) or tumor necrosis factor (TNF)-α, endothelium becomes activated as shown by expression of cell-adhesion molecules including myocardial vascular cell adhesion molecule (VCAM)-1 [4] immediately followed by an increase in endothelial permeability [5,6]. Endothelial permeability and subsequent
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