Biomedical subjects
H A Bruining
Publications and source records attributed to H A Bruining.
An experimental set-up to test heat-moisture exchangers.
OBJECTIVES: The purpose of this study was to build an experimental set-up to assess continuously the humidification, heating and resistance properties of heat-moisture exchangers (HMEs) under clinical conditions. DESIGN: The experimental set-up consists of a patient model, measurement systems and a ventilator. SETTING: Surgical ICU, University Hospital of Rotterdam. MATERIALS: A clinically used HME. MEASUREMENTS AND RESULTS: The air flow, pressure in the ventilation circuit, pressure difference over the HME, and partial water vapour pressure and temperature at each side of the HME were measured. The resistance, absolute humidity, humidification efficiency and temperature difference at the patient side of the HME were calculated. Measurements were performed during 24 h. The temperature output, humidity output and lung mechanics of the patient model were similar to values found in mechanically ventilated patients. The measurement system was in agreement with the ISO draft standard and was capable of measuring dynamic variation of water and heat exchange over the range of a clinically used ventilator setting. CONCLUSION: The experimental set-up described is reliable for evaluating HMEs and can also be used for future clinical evaluation of HMEs. The main advantages of this set-up over those described previously are: (i) measurements of dynamic variations of water and heat exchange; (ii) on-line measurements of expiratory, as well as inspiratory resistance.
Late haemorrhage from the subclavian vein due to a fracture of the first rib.
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Controlled clinical trial of selective decontamination for the treatment of severe acute pancreatitis.
OBJECTIVE: A randomized, controlled, multicenter trial was undertaken in 102 patients with objective evidence of severe acute pancreatitis to evaluate whether selective decontamination reduces mortality. SUMMARY BACKGROUND DATA: Secondary pancreatic infection is the major cause of death in patients with acute necrotizing pancreatitis. Controlled clinical trials to study the effect of selective decontamination in such patients are not available. METHODS: Between April 22, 1990 and April 19, 1993, 102 patients with severe acute pancreatitis were admitted to 16 participating hospitals. Patients were entered into the study if severe acute pancreatitis was indicated, on admission, by multiple laboratory criteria (Imrie score > or = 3) and/or computed tomography criteria (Balthazar grade D or E). Patients were randomly assigned to receive standard treatment (control group) or standard treatment plus selective decontamination (norfloxacin, colistin, amphotericin; selective decontamination group). All patients received full supportive treatment, and surveillance cultures were taken in both groups. RESULTS: Fifty patients were assigned to the selective decontamination group and 52 were assigned to the control group. There were 18 deaths in the control group (35%), compared with 11 deaths (22%) in the selective decontamination group (adjusted for Imrie score and Balthazar grade: p = 0.048). This difference was mainly caused by a reduction of late mortality (> 2 weeks) due to significant reduction of gram-negative pancreatic infection (p = 0.003). The average number of laparotomies per patient was reduced in patients treated with selective decontamination (p < 0.05). Failure of selective decontamination to prevent secondary gram-negative pancreatic infection with subsequent death was seen in only three patients (6%) and transient gram-negative pancreatic infection was seen in one (2%). In both groups of patients, all gram-negative aerobic pancreatic infection was preceded by colonization of the digestive tract by the same bacteria. CONCLUSION: Reduction of gram-negative colonization of the digestive tract, preventing subsequent pancreatic infection by means of selective decontamination, significantly reduces morbidity and mortality in patients with severe acute necrotizing pancreatitis.
Temperature-induced down-regulation of the glucocorticoid receptor in peripheral blood mononuclear leucocyte in patients with sepsis or septic shock.
OBJECTIVE: Activation of the hypothalamic-pituitary-adrenal axis is of vital importance during critical illness. We have studied the adaptive mechanisms which occur at the level of the glucocorticoid receptor in glucocorticoid target tissues in patients with sepsis or septic shock. DESIGN: The effects of hypercortisolaemia, hyperthermia and cellular composition on number of glucocorticoid receptors per cell and their affinity were evaluated, both in vitro and in vivo, in peripheral blood mononuclear leucocytes of control subjects and in patients with sepsis or septic shock. SUBJECTS: Fifteen patients (age 25-79) with sepsis or septic shock who were admitted to an intensive care unit were studied. The control group consisted of 24 healthy laboratory employees. MEASUREMENTS: The binding capacity and affinity of the glucocorticoid receptors were measured and compared to clinical data and the plasma cortisol concentrations. RESULTS: Hypercortisolaemia, in vitro, resulted in a decreased affinity and a decreased binding capacity of the glucocorticoid receptor. In vitro, hyperthermia as well as variations in the cellular composition did not influence the glucocorticoid receptor. In vivo, there was no change in the number of receptors per cell in patients with sepsis or septic shock as compared to healthy controls. However, a decreased affinity of the glucocorticoid receptor was observed. There was a weak but significant negative correlation between body temperature and the number of glucocorticoid receptors in the patient group. There was no relation between circulating cortisol concentrations and glucocorticoid receptor affinity and number. CONCLUSIONS: There is no obvious regulation of the number of glucocorticoid receptors by plasma cortisol concentrations in vivo. The decreased affinity of the glucocorticoid receptor together with the negative correlation between hyperthermia and the number of glucocorticoid receptors in patients with sepsis or septic shock suggest that hypothalamic-pituitary-adrenal axis activation during critical illness is accompanied by peripheral adaptation in glucocorticoid receptor number and affinity.
Increase of cardiac work is associated with decrease of mitochondrial NADH.
In this study we investigated the effect of work and substrate supply on mitochondrial NADH/NAD+ using epicardial autofluorescence in rat hearts perfused according to Langendorff. To avoid vasoconstrictor effects during high work output, nitroprusside-containing Tyrode solution was used. Photobleaching was avoided by using discontinuous ultraviolet excitation for NADH fluorescence measurements. To increase work, heartbeat rate was raised from 5 to 7 Hz, and concomitantly left ventricular pressure was raised stepwise from 0 to +/- 90 mmHg. During substrate-limited (5.5 mM glucose) perfusions, increase in O2 consumption (3.5 +/- 0.4 mumol.min-1.g-1, mean +/- SE, n = 6) caused by increase of heartbeat rate was associated with a significant decrease of NADH fluorescence (-31 +/- 2.5%, mean +/- SE, n = 6). During perfusions with 10 mM pyruvate increase of O2 consumption (3.6 +/- 0.7 mumol.min-1.g-1, mean +/- SE, n = 6) was associated with significant decrease of NADH fluorescence (-20 +/- 2.6%, mean +/- SE, n = 6). These results suggest that a rise in mitochondrial NADH/NAD+ is not the primary stimulus for increase in respiration and that changes of mitochondrial NADH/NAD+ are secondary to changes in O2 consumption.
Acute dialytic support for the critically ill: intermittent hemodialysis versus continuous arteriovenous hemodiafiltration.
There is still debate about whether continuous renal replacement therapy is superior to intermittent hemodialysis (IHD) as dialytic support for the critically ill patient with acute renal failure, mainly because of lack of comparative data. We sought to address this issue by reviewing the medical records of such patients admitted to a single surgical intensive care unit treated with either continuous arteriovenous hemodiafiltration (CAVHD) or IHD between January 1, 1986, and August 31, 1993. Of 94 consecutive patients who received dialytic support for severe acute renal failure, 34 (36%) patients were treated with IHD and 60 (64%) patients with CAVHD. The patients were comparable in terms of age or gender and represented a similar case mix. Patients treated with CAVHD were more severely ill as manifested by a lower mean arterial pressure (75 +/- 3 vs. 86 +/- 5 mm Hg; p < 0.05), higher Apache II score (26.5 +/- 0.5 vs. 22.2 +/- 0.3; p < 0.05), and a higher number of organ system failures (3.4 +/ 0.2 vs. 2.6 +/- 0.3; p < 0.05). Despite greater illness severity and a higher probability of death (55 +/- 2.6 vs. 33 +/- 2.5%; p < 0.0001), in those treated with CAVHD, no difference in outcome was observed between groups: CAVHD 26/60 (43%) vs. IHD 20/34 (59%; NS). The mean Apache II score of patients treated with CAVHD who survived was similar to that of patients treated with IHD who died (24.5 +/- 0.3 vs. 24.2 +/- 0.4; NS).(ABSTRACT TRUNCATED AT 250 WORDS)
High-risk surgical acute renal failure treated by continuous arteriovenous hemodiafiltration: metabolic control and outcome in sixty patients.
The outcome and metabolic control was studied in 60 critically ill patients with acute renal failure (ARF) treated by continuous arteriovenous hemodiafiltration (CAVHD) in a single surgical intensive care unit. Mean age (+/- SEM) was 60 +/- 2 years with a male predominance (80%). The majority of patients required mechanical ventilation (83%) and/or vasopressor support (70%) and suffered from multiorgan failure [mean number of organ system failures 3.3 +/- 0.3 (range 1-6)]. CAVHD resulted in a rapid decline of serum urea and creatinine levels during the first 72 h (urea 47.4 +/- 2.3 to 30.3 +/- 1.4 mmol/l, p < 0.05, and creatinine 572 +/- 27 to 361 +/- 23 mumol/l, p < 0.05); thereafter, controlled steady-state levels were achieved with serum urea levels kept below 30 mmol/l with full protein alimentation and often despite hypotension, surgery and septicemia. Significant electrolyte derangements could be easily corrected and maintained within normal limits. Bicarbonate homeostasis could be restored within 48 h in patients with severe metabolic acidosis (HCO3- < 20 mmol/l) with use of bicarbonate as a buffering anion (17 +/- 0.5 to 23.2 +/- 0.6, p < 0.05). CAVHD allowed rapid removal of excess body and lung water (up to 5 liters/day) without hemodynamic instability. Despite a mean pretreatment APACHE II score of 26.5, 26 patients (43%) survived until discharge from the intensive care unit, of whom 23 (38%) survived to leave hospital. Requirement of mechanical ventilation or vasopressor support, higher APACHE II scores and septicemia were all associated with a poor prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)
Inhibition of nitric oxide synthesis causes myocardial ischemia in endotoxemic rats.
Inhibitors of nitric oxide (NO) synthesis have been used in the treatment of septic and endotoxic shock. However, several studies question the beneficial effect of inhibiting NO production in sepsis and endotoxemia. We have investigated the effect of inhibition of NO synthesis after endotoxemia in the isolated perfused rat heart. In hearts from endotoxin-treated animals, coronary flow was elevated 64% and oxygen consumption was elevated 20% compared with control hearts. NADH fluorescence imaging was used as an indicator of regional hypoperfusion. A homogeneous low-surface NADH fluorescence, indicative of adequate tissue perfusion, was observed in both control and endotoxin-treated hearts. The increase in coronary flow and oxygen consumption could only partially be prevented by pretreatment of the animals with dexamethasone. Addition of N omega-nitro-L-arginine (NNLA), an inhibitor of NO synthesis, to the perfusion medium eliminated differences in coronary flow and oxygen consumption between normal and endotoxin-treated hearts. However, NADH surface fluorescence images of endotoxin-treated hearts after NNLA revealed areas of high fluorescence, indicating local ischemia, whereas the control hearts remained without signs of ischemia. The ischemic areas were present at various perfusion pressures and disappeared after the infusion of L-arginine, the natural precursor of NO, or the exogenous NO donor sodium nitroprusside. Methylene blue (MB), an inhibitor of soluble guanylate cyclase, the effector enzyme of NO, also eliminated differences in coronary flow and produced similar areas of local myocardial ischemia in endotoxin-treated hearts but not in control hearts.(ABSTRACT TRUNCATED AT 250 WORDS)
Differential adaptation of glucocorticoid sensitivity of peripheral blood mononuclear leukocytes in patients with sepsis or septic shock.
In view of the immunosuppressive action of glucocorticoids (GCs), the activation of the hypothalamo-pituitary-adrenal axis in patients with sepsis or septic shock is paradoxical. At the same time, administration of GCs to these patients is not clearly beneficial. We investigated the role of GCs in severe illness by measuring the sensitivity of peripheral blood mononuclear leukocytes to GCs in a mitogen-stimulated lymphocyte proliferation assay. In addition, we studied the role of interleukin-2 and several other cytokines in this system. Cells from patients with sepsis or septic shock (n = 15) were more sensitive to the antiproliferative action of GCs than were cells from normal controls (IC50 6.7 +/- 2.1 nmol/L for patients vs. 19.5 +/- 2.5 nmol/L for controls; P < 0.01). This increased sensitivity of the peripheral mononuclear cells to dexamethasone during the period of sepsis normalized during the ensuing period of clinical recovery of these patients. Dexamethasone inhibited the production of interleukin-2 in the mitogen-stimulated cells. Addition of interleukin-2 antagonized the suppressive effects of dexamethasone in a dose-dependent manner, both in cells from controls and in cells from patients with sepsis. To a lesser extent, the combination of interleukin-1, interleukin-6, and tumor necrosis factor-alpha also counteracted the effects of dexamethasone. In conclusion, our results suggest that not only the activity of the hypothalamo-pituitary-adrenal axis but also the sensitivity to GCs is regulated during sepsis and septic shock. Generally there is an increased sensitivity to GCs, which might help to protect the organism as a whole through supportive effects on metabolism and vasculature. This hypersensitivity is counteracted, possibly at the site of inflammation, by high local concentrations of cytokines. This would enable an adequate local response of the immune system in the presence of elevated cortisol levels. In view of the increased sensitivity of peripheral leukocytes to GCs, treatment of these patients with high doses of GCs may not be beneficial or may even be harmful.
[Dutch results of the European study of the prevalence of infections during intensive care (EPIIC). I. Who is at risk?].
OBJECTIVE: Evaluation of the point prevalence of infections acquired in an intensive care unit (ICU) and determination of risk factors for ICU patients. DESIGN: Descriptive study. SETTING: 78 Dutch ICUs. METHOD: Collecting data by detailed questionnaires for each patient admitted to one of the participating ICUs, on one specified day: April 29th, 1992. Follow-up lasted 6 weeks. RESULTS: Included in the study were 472 patients; 176 (37%) suffered from an infection, of which 74 (16%) was ICU-acquired. The most important risk factors were: a longer ICU stay (relative risk (RR) 4.23 (95% confidence interval: 3.32-5.40), 99.37 (22.26-434.50) and 146.79 (32.83-656.30) for ICU stays of 3-4 days, 1-2 and more than 3 weeks respectively, in comparison with 0-2 days), correlated with severity of disease (organ dysfunction) and more medical interventions (intubation, urine catheter). The ICU infection risk was lower after elective surgery than after ICU admission without surgery; after emergency surgery the ICU infection risk was higher. During follow-up 63 (14%) patients died. Patients suffering from an ICU infection had a higher mortality risk; the strongest prognostic factor in determining the mortality risk was the APACHE II score (RR: 13 (3.89-42.69) with a score between 16-26 and RR > 100 (7.67-1377.93) with score > 31). CONCLUSION: ICU-acquired infections are a serious problem. Programmes for infection prevention and control need to be adjusted.
[Dutch results of the European study of prevalence of infection during intensive care (EPIIC). II. Nature of the infections].
OBJECTIVE: Evaluation of the point prevalence of ICU-acquired infections, the type of infection, the bacteriological cultures and the antibiotics used. DESIGN: Point prevalence study. SETTING: 78 Dutch ICUs, as part of ICUs in 17 West-European countries. METHOD: Collecting data by detailed questionnaires for each patient admitted to one of the participating ICUs, on one specified day: April 29th, 1992. Follow-up lasted 6 weeks. RESULTS: The most frequently diagnosed ICU-acquired infections were pneumonia and infections of the lower respiratory tract (together 63%), followed by urinary tract infections (16%), sepsis (16%) and wound infections (11%). The most frequently cultured pathogens were Gram-negative bacteria (92%), especially Enterobacteriaceae (34%) and Pseudomonas aeruginosa (30%), followed by Staphylococcus (37%), Enterococcus (20%) and surprisingly: 10% fungi. The most-prescribed antibiotics were the cephalosporins (30%), followed by broad-spectrum penicillins (17%), metronidazole (17%) and aminoglycosides (13%). On the day of this survey there was in the Netherlands no infection with MRSA (Methicillin Resistant Staphylococcus aureus), although gentamicin resistant coagulase-negative Staphylococcus and ciprofloxacin-resistant P. aeruginosa were present. In most of the hospitals in the Netherlands, microbiologists, infectious disease specialists (84%) and infection control nurses (51%) take part in the ICU team. Half of the hospitals use selective decontamination. CONCLUSION: ICU-acquired infections are a real threat to the ICU patient. Despite a cautious antibiotics management in the Netherlands, resistance remains a serious problem.
[Preoperative noninvasive tests for localization of enlarged parathyroid glands in 115 patients with hyperparathyroidism].
OBJECTIVE: To evaluate results of preoperative localisation techniques in patients operated for hyperparathyroidism (HPT). SETTING: Rotterdam University Hospital. DESIGN: Retrospective study. METHOD: Results of 4 non-invasive preoperative localisation techniques in 115 patients with HPT were compared with operative findings of 116 explorations. Sensitivity and specificity were calculated for single versus multiple gland disease, primary exploration versus re-explorations and anatomical versus ectopic localisation. RESULTS: Sensitivity of preoperative ultrasound, thallium-technetium subtraction scintigraphy, computed tomography and 99mTc-sestamibi (MIBI) scanning in patients with single gland disease was 56%, 65%, 67% and 83% respectively. In multiple gland disease preoperative localisation techniques were much less successful. For MIBI scintiscanning this question remains unanswered. Specificity of all techniques was high. Success rates of preoperative localisation studies for primary operations and re-explorations were similar. Mean weight of parathyroid tumours that were missed preoperatively was lower than of successfully localised tumours. Only computed tomography and thallium-technetium scintigraphy were able to localise retrosternal parathyroid tumours. CONCLUSION: Review of the literature reveals that there is additional benefit of the preoperative localisation studies in re-exploration for HPT, in contrast to primary exploration. By combining localisation techniques more tumours are visualised. Preliminary results of MIBI scanning are favourable.
Current role of extracorporeal shockwave therapy in surgery.
In urology the introduction of extracorporeal shockwave therapy brought a revolutionary change to the management of urinary calculi. This inspired the introduction of shockwave therapy in several fields of surgery; it has been applied as a potential alternative to several operative procedures but is still experimental. So far, the major application of shockwave therapy has been lithotripsy of stones in the gallbladder, common bile duct, pancreatic duct and salivary gland ducts. Other applications are in the non-operative management of bone healing disturbances and in the inhibition of tumour growth. Steps towards selective thrombus ablation and pretreatment of heavily calcified arteries have also been made. In this review, the applications of extracorporeal shockwave therapy in several areas of surgery are discussed. It is concluded that, for selected patients, shockwave treatment may serve as a useful addition to the surgical armamentarium.
An inflated condom as a packing device for control of haemorrhage.
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A new phosphorimeter for the measurement of oxygen pressures using Pd-porphine phosphorescence.
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Intestinal ischemia during hypoxia and experimental sepsis as observed by NADH videofluorimetry and quenching of Pd-porphine phosphorescence.
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Effect of ketanserine on oxygenation and ventilation inhomogeneity in pigs with ARDS.
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