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Biomedical subjects

M Wendt

Publications and source records attributed to M Wendt.

At least 19 recordsLinked to original sources
PubMed1992

Gas exchange impairment and pulmonary densities after cardiac surgery.

In 11 patients with impaired respiratory function after coronary artery revascularization surgery, thoracic computed tomography (TCT) and cardiopulmonary profile were obtained. The patients were haemodynamically stable without clinical or radiological signs of lung oedema. Oxygenation was reduced in all patients (alveolo-arterial PO2-difference (PA-aO2) = 37.3 +/- 10.39 kPa, venous admixture (QVA/QT) = 26.4 +/- 4.4%) during mechanical ventilation with positive end-expiratory pressure (PEEP = 5 cmH2O) (0.5 kPa). TCT-scan analysis revealed considerable amounts of crest-shaped bilateral densities in dependent lung regions. There were no differences between the right and left hemithorax. Atelectatic lung tissues were defined as areas presenting with attenuation values of -200 to +20 Hounsfield Units. The magnitude of non-ventilated areas correlated with QVA/QT (r = 0.875, P < or = 0.01), but not with the duration of either extracorporeal circulation, surgical procedure or general anaesthesia. It is concluded that atelectasis in dependent lung areas contributes to impaired gas exchange after cardiac surgery.

Aged↗
PubMed1992

[Selenium poisoning in fattening swine].

A case of selenium toxicosis was observed in fattening pigs. Intoxication was caused by high levels of selenium in a commercial mineral premix. Instead of the recommended dose of 16 ppm Se, the mineral feed contained selenium at concentrations of 657 and 1059 ppm. The ration in use was found to contain more than 14 ppm selenium. Clinical symptoms were observed 5 to 6 weeks after the pigs began consuming the contaminated feed mixture. Feed intake was markedly reduced and animals showed severe lameness due to separation and necrosis of the hoof wall at the coronary band. Some pigs were reluctant to stand. In some cases alopecia was detected. At histopathological examination one animal with paralysis of the hind limbs revealed a focal bilaterally symmetric poliomyelomalacia in the lumbar segment of the spinal cord. Diagnosis was confirmed by high selenium contents of liver, kidneys and blood. After removing the incriminated feed no further pigs developed signs of intoxication. New horn growth was present and lame animals recovered slowly.

Alopecia↗
PubMed1991

High frequency jet ventilation in experimental pulmonary emphysema.

The effects of high frequency jet ventilation (HFJV, f = 2 Hz and 8 Hz, I:E = 0.43, FiO2 = 0.4) were studied and compared with intermittent positive pressure ventilation (IPPV, f = 10-14 breaths/min, VT = 15 ml/kg, I:E = 0.5, FiO2 = 0.4) in 8 dogs before and after induction of panlobular emphysema (PLE). PLE increased alveolar-arterial PO2 difference (PA-aO2) during all modes of ventilation, whereas PaCO2 did not change significantly. In both periods of the study, HFJV8 Hz was less effective in terms of CO2-elimination and oxygenation. In the control-period, functional residual capacity (FRC) was 937 +/- 212 ml. The increase during HFJV (HFJV2 Hz: 1156 +/- 508 ml, HFJV8 Hz: 1153 +/- 433 ml) did not reach significance (P = 0.09). Closing volume (CV) increased from 1.5 +/- 4.3% of vital capacity (%VC) (IPPV) to 6.3 +/- 7.1%VC (HFJV2 Hz) and 10.8 +/- 9.8% VC (HFJV8 Hz), respectively. In the PLE-period, FRC and CV increased significantly to 1107 +/- 207 ml and 14.1 +/- 7.0% VC respectively during IPPV (P less than 0.05). Application of HFJV neither increased FRC (HFJV2 Hz: 1153 +/- 433 ml, HFJV8 Hz: 1005 +/- 344 nor CV 14.8 +/- 6.0% VC and 13.9 +/- 8.1% VC, respectively). It is concluded that HFJV induces no alveolar overdistension in dogs with emphysematous lungs.

Animals↗
PubMed1991

[Artificial respiration in the prone position in a case of acute respiratory distress syndrome].

A patient is presented in whom an acute respiratory distress syndrome (ARDS) developed after severe lung contusion. Exchange of gas was markedly restricted under aggressive respiration (FiO2 = 1.0, PEEP = 10 mmHg, breathing time quotient = 0.5, respiratory minute volume = 16 litres; gas exchange values: PaO2 = 67 mmHg, PaCO2 = 45 mmHg, PA-aO2 = 461 mmHg). After control of the computed tomogram of the lungs showed marked densifications in those parts of the lung that are lower most by gravitation according to the positioning of the patient at a particular time the patient was ventilated in ventricumbent (prone) position for 60 hours. After having remained in this position for 48 hours, there was a significant improvement in the gas exchange (PaO2 = 89 mmHg, PaCO2 = 36 mmHg, PA-aO2 = 77 mmHg at FiO2 = 0.3, PEEP = 6 mmHg, breathing time quotient = 0.5 and respiratory minute volume = 9 litres). The control CT in dorsal position showed that the dorsal densifications had disappeared completely. Five days later the patient could be extubated. Respiration in ventricumbent (prone) position may considerably improve oxygenation by perfusion of well-ventilated regions of the lung that are lower-most by gravitation according to the relative positioning of the patient. Besides regions not well ventilated or not ventilated at all (according to the patient's position) may be better ventilated or re-opened and made accessible to ventilation by this method.

Adult↗
PubMed1991

Cardiopulmonary effects of constant-flow ventilation in experimental myocardial ischaemia.

The cardiopulmonary effects of constant-flow ventilation were investigated in dogs with normal heart function (control-phase, n = 14) and after development of acute myocardial ischaemia (ischaemia phase, n = 14). Heated, humidified and oxygen-enriched air was continuously delivered with an inspiratory flow rate of 1.21.kg-1.min-1 via two catheters positioned within each mainstem bronchus. Continuous positive pressure ventilation with a positive end-expiratory pressure of 0.5 kPa (5 cmH2O) was used as a reference. During control, neither continuous positive pressure ventilation nor constant-flow ventilation showed impairment of cardiopulmonary performance. Oxygenation and CO2 removal were more efficiently achieved by continuous positive pressure ventilation (P less than or equal to 0.05). Acute myocardial ischaemia was induced by occlusion of the left anterior descending (LAD) coronary artery; measurements during the ischaemia phase were performed 60 min following LAD occlusion. Myocardial ischaemia resulted in moderate changes of cardiac output, left ventricular end-diastolic pressure and dP/dtmax. Both modes of ventilation were well tolerated in the ischaemia phase, and cardiovascular performance revealed no significant differences between continuous positive pressure ventilation and constant-flow ventilation. Haemodynamic parameters could be more precisely assessed during constant-flow ventilation. Oxygenation deteriorated, but hypoxaemia did not occur in any animal and CO2 elimination remained unchanged. It is concluded that 'non-conventional' ventilation by continuous intrabronchial gas flow maintains adequate gas exchange with no adverse effects on haemodynamics in dogs with acute myocardial ischaemia. Constant-flow ventilation may be advantageous in the experimental setting to study cardiac function without cyclic heart-lung interaction due to airway pressure alterations.

Animals↗
PubMed1991

Cardiopulmonary effects of internal cardioverter/defibrillator implantation.

Cardiopulmonary effects of electrophysiological testing of internal cardioverter/defibrillator (ICD) devices were studied in ten patients undergoing general anaesthesia. In the control-phase, haemodynamic performance and oxygenation were slightly impaired. After completion of the electrophysiological procedures (ICD-phase), cardiopulmonary function had deteriorated significantly. Cardiac index declined by 16%, whereas left ventricular filling pressure and pulmonary vascular resistance increased (P less than or equal to 0.01). Oxygenation, but not CO2-elimination deteriorated (P less than or equal to 0.01) and venous admixture increased by 72% (P less than or equal to 0.01). Alveolo-arterial PO2-difference (PA-aO2) increased by 43% (P less than or equal to 0.01), indicating ventilation-perfusion (VA/Q) mismatching. Repeated inductions of ventricular tachycardia and/or fibrillation subject the myocardium to transient global ischaemia, leading to acute congestive heart failure, and positive inotropic intervention was necessary in 40% of the patients. Partial pulmonary insufficiency resulted possibly from interstitial oedema and VA/Q-inhomogeneities. ICD implantation has detrimental effects on haemodynamics and gas exchange in patients with impaired left ventricular function.

Aged↗
PubMed1991

Rupture of the spleen caused by primary angiosarcoma. Case report.

Splenic angiosarcoma is rare with only about 60 reported cases. A case is presented in which the tumor caused spontaneous rupture of the spleen and showed characteristics of an infiltrating echinococcosis of the liver and spleen in ultrasound and computed tomography imaging. The literature is reviewed in regard to clinical features, diagnosis and management.

Diagnostic Errors↗
PubMed1991

[Creatinine clearance as the foundation for clinical determination of kidney function in swine].

Comparative examinations of renal function using inulin- and endogenous creatinine-clearance tests in 5 pigs showed nearly identical values of glomerular filtration rate (GFR). Based on this relation 79 healthy pigs, weighting 2 kg to 230 kg were investigated using the creatinine-clearance test for determination of normal values of GFR and urine flow rate (Vu) as well as renal excretion (E), renal clearance (Clr) and fractional excretion (FE) of urea, sodium, potassium, calcium, phosphorus, glucose and lactate. The renal excretion of creatinine (E-Creat) was closely correlated with the body weight. Therefore it is possible to use the body weight for estimation of E-Creat and to calculate GFR and Vu using plasma and urine concentrations of creatinine independent of a timed volumetric urine collection. Subsequently E, Clr and FE of electrolytes or other endogenous substances can be evaluated. Finally the practicability of this procedure for detection of disturbed glomerular filtration or tubular reabsorption was demonstrated in piglets suffering from colidiarrhoea and/or transmissible gastroenteritis.

Animals↗
PubMed1991

[The effect of PEEP-ventilation on gas exchange and airway closure in experimental pulmonary emphysema].

The benefits of mechanical ventilation with positive end-expiratory pressure (PEEP) are well documented, especially for patients with acute respiratory failure. PEEP increases functional residual capacity (FRC) and reduces closing volume (CV) and ventilation-perfusion mismatching. Little is known about the effects of PEEP in patients with chronic obstructive pulmonary disease, where closing volume and ventilation-perfusion mismatching are increased. We investigated the effects of PEEP in a canine model of panlobular emphysema (PLE). METHODS. After completion of control-period measurements, PLE was induced in eight dogs by intratracheal application of 20 ml aerosolized 16% papain solution. Three weeks later the effects of continuous positive-pressure ventilation (CPPV, PEEP 10 cmH2O) on gas exchange, FRC, and CV were investigated. Conventional intermittent positive-pressure ventilation (IPPV) served as reference. Measurements of CV were done using both the foreign gas bolus method and the single-breath oxygen test. FRC was determined by the nitrogen dilution technique. RESULTS. The papain-induced emphysema produced a deteriation in oxygenation, enlargement of FRC and CV, and an increase in quasi-static lung compliance. CPPV led to a further increase of FRC, but gas exchange was not improved nor was CV reduced. In the PLE period, mean pulmonary arterial pressures (MPAP) were higher during both modes of ventilation. CPPV tended to increase MPAP and pulmonary capillary wedge pressure when compared with IPPV. Systemic hemodynamic conditions were stable throughout the experiment. CONCLUSIONS. The application of PEEP to emphysematous lungs seemed to enlarge FRC, predominantly in the nondependent rather than in the dependent lung regions, which are prone to airway closure. In patients with emphysema, ventilation with PEEP may further deteriorate the impaired distribution of ventilation and thus counteract any improvement of gas exchange.

Animals↗
PubMed1990

[Comparative studies of the detection of Corynebacterium suis infections in swine by indirect immunofluorescence and culture].

In a comparative study 47 urine samples of sows and 9 swabs of preputial diverticulum of boars were investigated for detection of Corynebacterium suis (Eubacterium suis) using an indirect immunofluorescent technique, a Gram stained preparation, a direct culture technique and a culture technique after enrichment. Examinations show that the indirect immunofluorescent technique and the enriched culture technique provide the best results, but that the fluorescent technique saves time and expenses. Additionally in contrast to culture techniques the detection of C. suis is not affected by accompanying bacteria. Using an indirect immunofluorescence it is possible to detect antibody-coating of C. suis in urine sediment of sows as well. There were close correlations between evidence of antibody-coated C. suis and the presence of an ascending pyelonephritis.

Animals↗
PubMed1990

Constant-flow ventilation during experimental left ventricular failure.

The efficacy of constant-flow ventilation (CFV) was investigated in dogs with normal heart function (control phase, n = 8) and after development of left ventricular failure (LVF phase, n = 8). Heated, humidified and oxygen-enriched air (inspired oxygen fraction (Fio2) = 0.4) was continuously delivered via two catheters positioned within each mainstem bronchus at two flow rates (1.2 and 1.6 l/kg/min). Conventional mechanical ventilation (CMV) with positive end-expiratory pressure (PEEP) of 0.5 kPa was used as reference ventilation. During control, neither CMV with PEEP nor CFV revealed severe impairment of cardiopulmonary performance. Alveolo-arterial PO2 difference (P(A-a)O2) increased significantly during CFV1.2 and CFV1.6, indicating a higher degree of ventilation-perfusion (VA/Q) inhomogeneity. Acute left ventricular failure (LVF) was induced by proximal occlusion of the left anterior descending (LAD) coronary artery. Cardiac output (CO), maximum velocity of pressure development (dP/dtmax) and mixed venous PO2 decreased (P less than or equal to 0.05), whereas left ventricular end-diastolic pressure (LVEDP) and pulmonary capillary wedge pressure (PCWP) increased (P less than or equal to 0.05). Extravascular lung water (EVLW), as determined by thermal-dye technique, increased from 10.1 ml/kg to 20.9 ml/kg (P less than or equal to 0.01). Oxygenation, but not CO2 elimination, deteriorated in the LVF phase. There were no haemodynamic differences between CMV with PEEP and CFV1.2, but cardiopulmonary performance deteriorated with CFV1.6. Gas exchange was significantly more impaired during CFV1.2 and CFV1.6 due to increased VA/Q mismatching. However, there were no significant differences for P(A-a)O2 values between CFVControl and CFVLVF.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Corynebacterium suis infections in swine. 2. Morphological findings in the urinary tract with special reference to the bladder].

Morphological investigations of the urethra, urinary bladder (2 localizations), ureter, renal pelvis and kidneys were performed in sows with Corynebacterium suis infection. The first stages of the disease were characterized by changes of the transitional epithelium in the bladder where epithelial vacuolisation, goblet cell differentiation, leucocytic infiltrations, and haemorrhages occurred. In chronically affected animals different stages of a mucopurulent, partly erosive to ulcerative cystitis were observed. Furthermore, chronic cystitis was characterized by polypoid mucosal proliferation and bacterial accumulations. Ureter and urethra showed signs of a mild purulent inflammation. In the renal pelvis there was a severe fibrinopurulent and necrotizing pyelitis which was accompanied by bacterial invasions. The parts of the renal pelvis without desquamation of the transitional epithelium undergo mucoid degenerations. The final stage of the disease is characterized by severe fibrosing chronic interstitial nephritis leading to death of the animals due to uraemia.

Animals↗
PubMed1990

[Comparative studies of the clearance of inulin and creatinine in swine].

Endogenous creatinine clearance was determined in 5 healthy female pigs of different body weight simultaneously to the clearance of inulin. The average creatinine clearance (3.74 +/- 0.57 mg/min/kg) has been found to be 7% higher than inulin clearance indicating some tubular secretion of creatinine. However, since this difference was not significant, the endogenous creatinine clearance is a practicable method for the measurement of glomerular filtration rate in swine. Data of creatinine concentration in plasma and of creatinine excretion showed close relationships to the body weight. It is discussed, whether the glomerular filtration rate can be predicted from the creatinine concentration in plasma and creatinine excretion, which might be estimated from the body weight without quantitative urine collection.

Animals↗
PubMed1990

[Corynebacterium suis infection in swine. 1. Clinical diagnosis with special consideration of urine studies and cystoscopy].

Experimental and spontaneous infections with Corynebacterium suis in sows were investigated. In early stages animals show no clinical disorders or only for a short time. However, there are already marked changes in urinary samples (hematuria, proteinuria, leukocyturia, gross alterations). Using an endoscope mucosal irritations can be seen mainly on the floor of the bladders. In chronic cases alterations in urine are more pronounced. If a pyelonephritis is present in addition to the cystitis, general signs of illness are evident including anorexia, emaciation, anemia, subnormal body temperature and abortions. Bladders demonstrate an erosive and ulcerative, hemorrhagic cystitis on the whole mucosal surface. Uremia appears only in late stages of the disease.

Animals↗
PubMed1990

[Mixed venous versus central venous oxygen saturation in intensive medicine].

Mixed venous oxygen saturation (SvO2) has been established as a useful guide in observing whole body oxygenation. Since SvO2 provides limited information about adequate tissue oxygenation for a specific organ, the usefulness of central venous saturation (ScvO2) as a guide was analysed, which is a less invasive parameter. In 19 ICU patients 44 pairs of blood samples were drawn from a separate central venous catheter and from the tip of an SG-catheter. The correlation of oxygen partial pressures was 0.687 and the correlation of the saturation reached 0.779. The calculation of venous admixture showed a correlation of 0.901. It is concluded that ScvO2 yields adequate information on the oxygen saturation of venous return.

Catheterization, Central Venous↗
PubMed1990

[Secondary effects caused by feed medication in swine].

Giving medical feed to weanling pigs it is possible to produce a vitamin K-deficiency as a side effect, which is caused by destruction of the intestinal flora. In this investigation the effect of different drugs in a vitamin K-deficient diet on blood coagulation of weanling pigs was examined. In a first trial clinical symptoms of a vitamin K-dependent coagulation disorder could be seen in five from six animals after feeding a combination of sulfadimidine, tylosin, furazolidone and arsanilic acid. Animals showed haemorrhages, when they were housed on flatdecks as well as on concrete floor. This indicated that coprophagy plays no role in pigs for supply of vitamin K. Feeding these drugs in other combinations or one of the drugs alone caused no clinical signs in a second trial. Significant differences to untreated control pigs were found only in one group (sulfadimidine/arsanilic acid) for activities of coagulation factors. Other groups demonstrated only prolongation of clotting times in single animals. Pigs, which received sulfadimidine within their ration, were more often affected than other animals. In a third trial suckling pigs were treated over a period of three weeks with a drug combination used in the first trial to allow an adaptation of the intestinal flora. Same treatment after weaning was unable to produce any clinical symptoms, but led to distinct coagulation disorders in pigs treated before as well as in untreated animals. It is supposed that the development of a vitamin K-deficiency depends on faecal bacterial count and on the specific resistance of intestinal flora in individuals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1990

Hemofiltration in myoglobinuric acute renal failure.

The frequency of myoglobinuric renal failure is estimated between 8 and 20%. Despite early onset of therapy often the use of renal substitution by hemodialysis or hemofiltration is required. This study of the clinical course of nine patients with myoglobinuric acute renal failure reveals continuous arterio-venous hemofiltration (CAVH) to have an effective clearance for myoglobin. Thus, the time until recovery of renal function as well as the frequency of secondary complications in rhabdomyolysis induced acute renal failure can be distinctly reduced.

Acute Kidney Injury↗