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Biomedical subjects

J G van der Hoeven

Publications and source records attributed to J G van der Hoeven.

At least 19 recordsLinked to original sources
PubMed2006

Quantitative acid-base physiology using the Stewart model. Does it improve our understanding of what is really wrong?

Traditional theories of acid-base balance are based on the Henderson-Hasselbalch equation to calculate proton concentration. The recent revival of quantitative acid-base physiology using the Stewart model has increased our understanding of complicated acid-base disorders, but has also led to several new controversies. With the help of three patient histories, we show that the Henderson-Hasselbalch equation should be regarded as a simplified version of the more general Stewart model and not as something completely different. Therefore, both models may be useful at the bedside.

Journal Article↗
PubMed2005

Lung recruitment during mechanical positive pressure ventilation in the PICU: what can be learned from the literature?

A literature review was conducted to assess the evidence for recruitment manoeuvres used in conventional mechanical positive pressure ventilation. A total of 61 studies on recruitment manoeuvres were identified: 13 experimental, 31 ICU, 6 PICU and 12 anaesthesia studies. Recruitment appears to be a continuous process during inspiration and expiration and is determined by peak inspiratory pressure (PIP) and positive end expiratory pressure (PEEP). Single or repeated recruitment manoeuvres may result in a statistically significant increase in oxygenation; however, this is short lasting and clinically irrelevant, especially in late ARDS and pneumonia. Temporary PIP elevation may be effective but only after PEEP loss (for example disconnection and tracheal suctioning). Continuous PEEP elevation and prone positioning can increase P(a)O2 significantly. Adverse haemodynamic or barotrauma effects are reported in various studies. No data exist on the effect of recruitment manoeuvres on mortality, morbidity, length of stay or duration of mechanical ventilation. Although recruitment manoeuvres can improve oxygenation, they can potentially increase lung injury, which eventually determines outcome. Based on the presently available literature, prone position and sufficient PEEP as part of a lung protective ventilation strategy seem to be the safest and most effective recruitment manoeuvres. As paediatric physiology is essentially different from adult, paediatric studies are needed to determine the role of recruitment manoeuvres in the PICU.

Anesthesia↗
PubMed2005

Cytokines and biotrauma in ventilator-induced lung injury: a critical review of the literature.

BACKGROUND: Mechanical ventilation is known to induce and aggravate lung injury. One of the underlying mechanisms is biotrauma, an inflammatory response in which cytokines play a crucial role. OBJECTIVE: To review the literature on the role of cytokines in ventilator-induced lung injury (VILI) and multiple organ dysfunction syndrome (MODS). MATERIAL AND METHODS: 57 English written, peer-reviewed articles on cytokines in in-vitro settings (n=5), ex-vivo models (n=9) in-vitro models (n=19) and clinical trials (n=24). RESULTS: Mechanical ventilation (MV) can induce cytokine upregulation in both healthy and injured lungs. The underlying mechanisms include alveolar cellular responses to stretch with subsequent decompartimentalisation due to concomitant cellular barrier damage. The cytokines involved are interleukin (IL)-8 and CXC chemokines, and probably IL-6, IL-1beta and tumour necrosis factor (TNF)-alpha. Cytokines are important for signalling between inflammatory cells and recruiting leucocytes to the lung. There is strong circumstantial evidence that the release of cytokines into the systemic circulation contributes to the pathogenesis of MODS. Multiple studies demonstrate the relation between elevated proinflammatory cytokine concentrations and mortality. CONCLUSION: Cytokines are likely to play a role in the various interrelated processes that lead to VILI and other MV-related complications, such as MODS and possibly ventilatorassociated pneumonia. Cytokines are good surrogate endpoints in exploring the pathogenesis and pathophysiology of VILI in both experimental and clinical studies.

Animals↗
PubMed2004

[Nutrition and health--enteral nutrition in intensive care patients].

Nutritional therapy in the intensive care unit exerts favourable effects on morbidity and mortality. Enteral nutrition is preferable to parenteral nutrition. Only perforation or total obstruction of the gastrointestinal tract, proven mesenteric ischaemia and toxic megacolon are absolute contra-indications to enteral nutrition. Early enteral nutrition is effective in decreasing infectious complications and reducing the length of stay in the hospital. Nutrition that is enriched with specific ingredients in order to modulate the immune response is referred to as immunonutrition. The use of immunonutrition, notably in surgical intensive care patients, has a favourable effect on the incidence of infectious complications, the duration of artificial respiration and the length of hospital stay. The addition of glutamine to parenteral nutrition may reduce mortality compared to standard parenteral nutrition. Implementation of a simple feeding algorithm in the intensive care unit, with special attention for the treatment of delayed gastric emptying, is cost-effective and leads to an improvement in the nutritional parameters.

Adjuvants, Immunologic↗
PubMed2004

[Acute traumatic spinal cord injury and cardiovascular complications due to neurogenic shock: a possible threat for functional recovery].

Three men aged 18, 18 and 24 years, developed hypotension and bradycardia following an acute traumatic cervical or thoracic spinal cord injury. After treatment in intensive care and 1-12 months of rehabilitation they still suffered from considerable neurological disorders. Hypotension and bradycardia are common phenomena following acute traumatic cervical and thoracic spinal cord injury. Awareness of cardiovascular complications as a possible threat for functional recovery and adequate insight in the neurological cause of hypotension and bradycardia are important issues in the acute treatment of patients with spinal cord injury. It seems sensible to admit these patients to a medium-care or intensive-care department where they can be monitored and treated by a specialised team in accordance with an adequate protocol.

Acute Disease↗
PubMed2004

Emergency cricothyrotomy: a randomised crossover trial comparing the wire-guided and catheter-over-needle techniques.

In a randomised crossover trial, we compared a wire-guided cricothyrotomy technique (Minitrach) with a catheter-over-needle technique (Quicktrach). Performance time, ease of method, accuracy in placement and complication rate were compared. Ten anaesthesiology and 10 ENT residents performed cricothyrotomies with both techniques on prepared pig larynxes. The catheter-over-needle technique was faster than the wire-guided (48 compared to 150 s, p < 0.001) and subjectively easier to perform (VAS-score 2.1 vs. 5.6, p < 0.001). Correct positioning of the cannula could be achieved in 95% and 85%, respectively (NS). There was one complication in the catheter-over-needle group compared to five in the wire-guided group. We conclude that the wire-guided minitracheotomy kit is unsuitable for emergency cricothyrotomies performed by inexperienced practitioners. On the other hand, the catheter-over-needle technique appears to be quick, safe and reliable.

Animals↗
PubMed2004

Hypothesis: Normalisation of cytokine dysbalance explains the favourable effects of strict glucose regulation in the critically ill.

Recent trials investigating the effects of strict glucose regulation in critically ill patients have shown impressive reductions in morbidity and mortality. Although the literature focuses on the possible toxic effects of high blood glucose levels, the underlying mechanism for this improvement is unclear. We hypothesise that strict glucose regulation results in modulation of cytokine production, leading to a shift towards a more anti-inflammatory pattern. This shift in the cytokine balance accounts for the reduction in morbidity and mortality. To support our hypothesis, effects of glucose and insulin on cytokine release and effects of glucose, insulin, and cytokines on host defence, cardiac function and coagulation will be reviewed.

Blood Coagulation↗
PubMed2002

[Necrotising pancreatitis as an unexpected complication in seriously ill patients].

Three patients, two men aged 70 and 73 years, respectively, who underwent surgery due to an abdominal aortic aneurysm, and a woman aged 75 years, who was operated on due to acute arterial embolic occlusion of both legs, developed abdominal complaints post-operatively. These were found to be caused by necrotising pancreatitis. The accompanying fluid accumulation was drained percutaneously. Two patients recovered; the 73-year-old man died suddenly, possibly as a result of burst aortic sutures. In patients with a serious condition, necrotising pancreatitis should be considered in the case of a generalised inflammatory reaction and abdominal symptoms. Percutaneous drainage of infected necrotic tissue can sometimes improve the patient's condition, making surgery possible at a later stage.

Aged↗
PubMed2001

Atrial natriuretic peptide infusion and nitric oxide inhalation in patients with acute respiratory distress syndrome.

AIM: To study the effects of infusion of atrial natriuretic peptide (ANP) versus the inhalation of nitric oxide (NO) in patients with an early acute respiratory distress syndrome (ARDS). METHODS: Ten patients with severe ARDS were studied in a crossover study design, within 72 hours after starting mechanical ventilation. We studied the effects of ANP infusion (10 ng/kg/min for 1 hour) and of inhalation of NO (20 ppm for 1 hour) on hemodynamic and respiratory patient parameters, as well as the effects on plasma levels of ANP, guanosine 3',5'-cyclic monophosphate, nitrate and endothelin-1. RESULTS: Despite an approximate 50% increase in mixed venous ANP plasma concentration (from 86 +/- 21 to 123 +/- 33 ng/l, P < 0.05) during ANP infusion, there were no changes in mean pulmonary artery pressure, pulmonary vascular resistance index, extravascular lung water index, or in pulmonary gas exchange. NO inhalation, in contrast, lowered mean pulmonary artery pressure (from 26 +/- 1.9 to 23.9 +/- 1.7 mmHg, P < 0.01), pulmonary vascular resistance index (from 314 +/- 37 to 273 +/- 32 dynes/cm5/m2, P < 0.05) and central venous pressure (from 8.2 +/- 1.2 to 7.3 +/- 1.1 mmHg, P < 0.02). Furthermore, NO inhalation improved pulmonary gas exchange, reflected by a decrease in alveolar-arterial oxygen gradient (from 41.9 +/- 3.9 to 40.4 +/- 3.6 kPa, P < 0.05), a small increase in oxygenation (PaO2/FiO2 from 17.7 +/- 1.4 to 19.7 +/- 1.1 kPa, P = 0.07) and a small decrease in venous admixture (Qs/Qt from 35.7 +/- 2.0 to 32.8 +/- 2.7%, P = 0.11). CONCLUSION: This study shows that, in contrast to NO inhalation, infusion of ANP neither improves oxygenation nor attenuates pulmonary hypertension or pulmonary edema in patients with severe ARDS.

Administration, Inhalation↗
PubMed2000

Relationships between volume and pressure measurements and stroke volume in critically ill patients.

OBJECTIVE: To evaluate the relationships between the changes in stroke volume index (SVI), measured in both the aorta and the pulmonary artery, and the changes in intrathoracic blood volume index (ITBVI), as well as the relationship between changes in aortic SVI and changes in the pulmonary artery wedge pressure (PAWP). DESIGN: Prospective study with measurements at predetermined intervals. SETTING: Medical intensive care unit of a university hospital. PATIENTS AND METHODS: One hundred and fifty-four measurements were taken in 45 critically ill patients with varying underlying disorders. Aortic SVI and pulmonary arterial SVI were determined with thermodilution. PAWP was measured using a pulmonary artery catheter. ITBVI was determined with thermal-dye dilution, using a commercially available computer system. RESULTS: A good correlation was found between changes in ITBVI and changes in aortic SVI. However, this correlation weakened when changes in ITBVI were plotted against changes in pulmonary arterial SVI, which was in part probably due to mathematical coupling between ITBVI and aortic SVI. A good correlation between changes in ITBVI and changes in aortic SVI could also be established in most of the individual patients. No correlation was found between changes in PAWP and changes in aortic SVI. CONCLUSION: ITBVI seems to be a better predictor of SVI than PAWP. ITBVI may be more suitable than PAWP for assessing cardiac filling in clinical practice.

Aorta↗
PubMed2000

Extravascular lung water in patients with septic shock during a fluid regimen guided by cardiac index.

BACKGROUND: To elucidate whether patients with a septic shock develop pulmonary edema in a treatment protocol in which volume loading is guided by its effect on the cardiac output, rather than by preset values of pulmonary artery wedge pressure (PAWP). METHODS: 15 consecutive patients with the diagnosis of septic shock were studied in a prospective observational study. Cardiac output, PAWP and extravascular lung water index (EVLWI) were determined at regular intervals during the first 24 h of treatment. Fluid challenges were given if MAP was <80 mm Hg and/or CI was <4.5 l/min/m(2), and PAWP was <16 mm Hg. Further fluid challenges were only given if the preceding fluid challenge resulted in an increase in CI of more than 10% and PAWP was still <16 mm Hg. RESULTS: EVLWI was slightly above normal (10.4+/-1.2 ml/kg) and did not change during the treatment protocol. One third of the patients had an initial PAWP>16 mmHg. In these patients, EVLWI was significantly higher than in patients with an initial PAWP <16 mm Hg (14.1+/-1.1 ml/kg versus 10.0+/-0.9 ml/kg, P=0.026). No significant correlation was found between PAWP and EVLWI. CONCLUSION: In this study, patients with septic shock did not develop pulmonary edema during the first 24 h of treatment, when their fluid regimen was guided by the effects on cardiac output.

Adult↗
PubMed1999

Pulmonary artery wedge pressure and extravascular lung water in patients with acute cardiogenic pulmonary edema requiring mechanical ventilation.

This study describe the values of pulmonary artery wedge pressure (PAWP) and the extravascular lung water (EVLW) index in patients with acute cardiogenic pulmonary edema who require mechanical ventilation. Ten consecutive patients with acute cardiogenic pulmonary edema who required mechanical ventilation were studied. Cardiac index was determined with thermodilution. Central venous pressure and PAWP were measured with a pulmonary artery catheter. EVLW index was determined with the thermal dye dilution technique, using a commercially available computer system. Measurements were made at regular preset intervals after the initiation of mechanical ventilation. PAWP was normal at baseline (11.6+/-0.9 mm Hg, range 8 to 17) and did not change. EVLW index was elevated at baseline (13.7+/-1.5 ml/ kg) and decreased to a normal value after 24 hours (8.6+/-1.2 ml/kg, p = 0.02). Concomitantly cardiac index increased from 2.61+/-0.24 to 3.61+/-0.14 L/min/m2 (p = 0.05). There was no correlation between PAWP and EVLW index. Fluid balance was +1,221+/-908 ml after 24 hours and there was a weight gain of 0.88+/-1.06 kg after 24 hours. Thus, patients with acute cardiogenic pulmonary edema requiring mechanical ventilation may have a normal PAWP after mechanical ventilation has been initiated. In a hemodynamic unstable situation, these patients may require fluid challenges to improve cardiac output, despite the presence of pulmonary edema. The pulmonary edema, measured as EVLW index, resolves rapidly when cardiac performance improves, despite positive fluid balances and weight gain in the first 24 hours.

Acute Disease↗
PubMed1999

Prognostic significance of the difference between mixed venous and jugular bulb oxygen saturation in comatose patients resuscitated from a cardiac arrest.

To determine the prognostic significance of the difference between mixed venous and jugular bulb oxygen saturation in survivors and non-survivors of a cardiac arrest, we studied 30 comatose patients (21 non-survivors and 9 survivors) resuscitated from a cardiac arrest. We measured mixed venous oxygen saturation (SmvO2) and jugular bulb oxygen saturation (SjO2) immediately after haemodynamic stabilisation (always within 6 h after cardiac arrest) and 6, 12 and 24 h later. In all patients the SjO2 was about 10% lower than the SmvO2 in the first measurement. In the survivors the SjO2 did not change and remained lower than SmvO2 in eight of nine survivors. However, in the non-survivors the SjO2 increased significantly and was finally higher than the SmvO2 in 12 of 20 patients 24 h after cardiac arrest suggesting a decrease in cerebral oxygen consumption due to extensive loss of functional brain tissue. The positive predictive value of (SmvO2-SjO2) < or = 0 for predicting irreversible brain damage at 24 h after cardiac arrest is 93% and the negative predictive value of (SmvO2-SjO2) > 0 is 53%. Sensitivity and specificity are 65 and 89%, respectively. In a previous study we concluded that early jugular bulb oximetry (within 4 h after cardiac arrest) cannot predict cerebral outcome in comatose patients after cardiac arrest. More studies are needed to clarify the role of prolonged monitoring in the prediction of cerebral outcome after cardiac arrest.

Adult↗