[Clinical experiences with central venous multi-lumen catheters]

We retrospectively studied 617 insertions of multilumen-catheters in 570 cardiosurgical patients. Number of catheters, insertion technique, indwelling period, catheter insertion site, specific positions and complications of insertion were evaluated by anesthetic chart and chest x-ray. In most cases the catheters were placed by a percutaneous insertion lock in the right or left v. jugularis interna as main site. Early complications mainly occurred because of incorrect placements. Post-operative radiological control by chest x-ray nearly showed 67% malpositions mainly resulting from the catheter placed not sufficiently far within the insertion lock. Though the catheter initially was placed correctly, it slided back to the insertion lock under mechanical influence on the site of fixation. In only 3 of 617 cases we found a too far inserted catheter. In these cases insertion was made by a Seldinger guidewire after direct venipuncture.

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)

[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.

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.

[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)

[Introduction of a new card for the "bedside test"]

A new card for the obligatory ABO-group test is presented. There is sufficient space to perform the test by mixing patient and donor blood to the relevant antisera. As it does not offer any further information, testing for anti-AB has been deleted. Contaminated areas can easily be discarded afterward, minimizing any risk of infection. Only the documentation on the remaining portion of the card is legally important and needs to be entered into the patient's records. Choosing a new manufacturer has resulted in a very low price.

Statoliths and microfilaments in plant cells

Microfilaments have been demonstrated in rhizoids of Chara fragilis Desvaux by labelling of actin with rhodamine-conjugated phalloidin. Each rhizoid contains thick microfilament-bundles arranged longitudinally in the basal region. In the subapical and apical regions, much thinner bundles exist which contact the statoliths and encircle them in the form of a dense envelope. In root statocytes from Lepidium sativum L. the presence of an actin network is indicated by the fact that application of cytochalasin B (25 micrograms ml-1 for 4 h) results in an approximately threefold increase in the rate of statolith (amyloplast) sedimentation relative to controls. It is concluded that in gravity-perceiving plant cells statoliths may trigger the transduction mechanism via actin filaments.

The polarity of statocytes and the gravisensitivity of roots are dependent on the concentration of calcium in statocytes

In order to examine a possible role of calcium in graviperception, the calcium ionophore A23187 was used to elevate the concentration of free cytoplasmic calcium in statocytes of the roots of Lepidium sativum L. After a brief incubation (30 min) in a medium that contained 10 micromoles A23187 and 5.5 micromoles CaCl2, 50% of the roots bent gravitropically during a subsequent 2 h of horizontal exposure, with an angle of curvature that varied from 5 degrees to 70 degrees. The corresponding statocytes exhibited a polar arrangement of cell organelles as did the controls. However, in statocytes from 50% of the roots which were not curved after gravistimulation a portion of the distal endoplasmic reticulum (ER) complex was displaced in the direction of gravity within 30 min of horizontal exposure. After washing of the briefly treated roots for 24 h with 1% dimethylsulfoxide the percentage of gravitropically bending roots increased to approximately 80%, but the angle of curvature amounted to only 5 degrees-10 degrees. Longer treatment (2 h) with A23187 caused a complete loss of graviresponsiveness which was accompanied by disintegration of statocyte polarity. We concluded from these results that i) calcium is involved in graviperception and ii) gravisensitivity depends on the integrity of statocytes.

Constant-flow ventilation in canine experimental pulmonary emphysema

The efficacy of constant-flow ventilation (CFV) was investigated in eight mongrel dogs before (control-phase) and after development of papain-induced panlobular emphysema (PLE-phase). For CFV, heated, humidified and oxygen-enriched air was continuously delivered via two catheters positioned within each mainstem bronchus at flow rates (V) of 0.33, 0.5 and 0.66 l/s. Data obtained during intermittent positive pressure ventilation (IPPV) served as reference. In the control-phase, Pao2 was lower (P less than or equal to 0.05) and alveolo-arterial O2 difference (P(A-a)O2) was higher (P less than or equal to 0.01) during CFV at all flow rates when compared with IPPV. This may be due to inhomogeneities of intrapulmonary gas distribution and increased ventilation-perfusion (VA/Q) mismatching. Paco2 and V showed a hyperbolic relationship; constant normocapnia (5.3 kPa) was achieved at 0.48 +/- 0.21 l/s (V53). Development of PLE resulted in an increase of functional residual capacity (FRC), residual volume (RV) and static compliance (Cstat) (P less than or equal to 0.05). PaO2 had decreased and P(A-a)O2 had increased (P less than or equal to 0.05), indicating moderate pulmonary dysfunction. Oxygenation during CFV was not significantly different in the PLE-phase when compared with the control-phase. Paco2 and V showed a hyperbolic relationship and V5.3 was even lower than in the control-group (0.42 +/- 0.13 l/s). In dogs with emphysematous lungs CFV maintains sufficient gas exchange. This may be due to preferential ventilation of basal lung units, thereby counterbalancing the effects of impaired lung morphometry and increased airtrapping. Conventional mechanical ventilation is more effective in terms of oxygenation and CO2-elimination.

[Various heart arrhythmias in swine (short communication)]

Heart arrhythmias were observed in 7 of 147 pigs suffering from heart and circulatory insufficiencies. Endocarditis valvularis and cardiomypathy were the dominant causes of the arrhythmias. Electrocardiographic abnormalities of the cases are discussed.

Single breath N2 washout in papain-induced pulmonary emphysema

Single breath nitrogen washout tests were analyzed in dogs (n = 8) with healthy lungs and after development of emphysema. The animals were in the supine position and studied during anaesthesia and mechanical ventilation (FiO2 = 0.4, FiN2 = 0.6). During controlled expiration with constant flow (VE = 0.15 l/s) onset of phase IV of the alveolar plateau was related to airway closure of dependent lung regions (closing volume CV). In the control state, CV accounted for 6.2 +/- 1.5% VC, and closing capacity (CC) was lower than functional residual capacity (FRC). Likewise, gas exchange was normal in all animals (PaO2 = 24.7 +/- 3.32 kPa, PaCO2 = 5.18 +/- 0.53 kPa, PA-aO2 = 2.6 +/- 0.3 kPa). Panlobular emphysema (PLE) was induced by inhalation of papain (100 mg/kg). After three weeks development of PLE was documented by measurements of lung volumes (functional residual capacity (FRC), expired vital capacity (EVC), total lung capacity (TLC), residual volume (RV], pulmonary mechanics (dynamic and static compliance (Cdyn, Cstat), mean airway resistance (Raw], gas exchange (PaO2, PaCO2, PA-aO2), and by radiomorphological analysis. In the PLE-group, FRC and RV (p less than or equal to 0.05), and Cstat (p less than or equal to 0.01) were significantly elevated. CV increased to 16.2 +/- 2.7% VC (p less than or equal to 0.01) and CC exceeded FRC by 80 ml, indicating that tidal volume breathing took place within the range of closing volume. Oxygenation was significantly impaired (PaO2 = 18.6 +/- 3.72 kPa, PA-aO2 = 6.5 +/- 1.1 kPa, p less than or equal to 0.05), but not CO2-elimination. Pathological analysis by radiomorphological means showed dissiminate parenchymal lesions compatible with emphysema of grade II severity located predominantly in subpleural areas. In dogs with papain-induced PLE, premature closure of dependent airways is enhanced, which is due to structural changes and a loss of elastic recoil in the lungs.

[Magnetic resonance tomography: a patient-connected system for artificial respiration and monitoring]

Physical phenomena that occur during magnetic resonance imaging (MRI) and the position of the patient inside the scanning tube necessitate adaptations of anesthetic techniques and devices. An anesthesia unit is presented that operates in close proximity to the patient without interfering with the imaging process. This unit enables the anesthesiologist to be close to the patient and his equipment, and minimizes the length of necessary tubing between patient and anesthesia apparatus. The unit consists of commonly used, commercially available devices with only minor modifications.

High-frequency jet ventilation during oleic-acid induced pulmonary oedema

In oleic acid-induced pulmonary oedema (OAPO) sequential intrapulmonary fluid accumulation occurs leading to different expiratory flow pattern in dependent lung regions. The potential effects on efficacy of high-frequency jet ventilation (HFJV, f = 3 Hz, I: E = 0.43, FiO2 = 0.4) were studied and compared with continuous positive pressure ventilation (CPPV, f = 12-18/min, I:E = 0.5, TV = 12 ml/kg, PEEP = 0.5 kPa, FiO2 = 0.4) in a dog model of OAPO. In the control state (lung-healthy dogs), 15 min after oleic acid lung injury (interstitial oedema, period I) and 60 min after onset of OAPO (alveolar oedema, period II), gas exchange, lung volumes, compliance, resistance and haemodynamics were measured. The course of lung oedema was determined indirectly by means of washout curves of helium (foreign gas bolus-test, FGB) and nitrogen (single breath-test for oxygen, SBO2). During control, there were no significant differences between the HFJV-group (n = 7) and the CPPV-group (n = 6) by virtue of gas exchange, lung volumes and haemodynamics. During period I, PaO2 decreased significantly both with HFJV (p less than 0.01) and CPPV (p less than 0.05), being lower in the HFJV-group (p less than 0.05). PaCO2, pulmonary and haemodynamic parameters were unchanged. Onset of phase IV of the alveolar plateau (closing volume CV) occurred significantly earlier (p less than 0.05) in all animals. Impaired ventilation of dependent lung regions, increased maldistribution of intrapulmonary gas and VA/Q-mismatching may be the underlying mechanisms for lower efficacy of HFJV during interstitial lung oedema. In period II, pulmonary and cardiocirculatory parameters had changed significantly in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential ventilation with low-flow CPAP and CPPV in the treatment of unilateral chest trauma

A case of severe unilateral chest trauma with bronchopleural fistula is presented. Ventilatory therapy consisted of asynchronous independent lung ventilation (AILV). The injured lung was ventilated with intermittent positive pressure ventilation (IPPV) [tidal volume (TV) = 200 ml, f = 25/min, I:E = 0.5, minute volume (MV) = 5.0 l/min, FiO2 = 0.4], and the unaffected lung was ventilated with continuous positive pressure ventilation (CPPV) (TV = 600 ml, f = 12/min, I:E = 0.5, MV = 7.2 l/min, PEEP = 0.5 kPa, FiO2 = 0.4). Adequate gas exchange was obtained (PaO2 = 14.5 +/- 2.3 kPa, PaCO2 = 5.5 +/- 0.7 kPa), but high air leakage volumes persisted. Thus, differential low-flow CPAP (V = 5.0-7.5 l/min, PEEP = 0.5 kPa, FiO2 = 0.4) of the injured lung and CPPV (TV = 600 ml, f = 12/min, MV = 7.2 l/min, I:E = 0.5, PEEP = 0.5 kPa, FiO2 = 0.4) of the unaffected lung was applied for 36 hours. Further deterioration of pulmonary function was prevented, and the bronchopleural fistula closed after several hours. After another period of AILV the patient was treated with conventional mechanical ventilation, and finally weaned with high-flow CPAP.

[Catheter malposition following puncture of the left internal jugular vein]

A central venous catheter was inserted into the left internal jugular vein but was abnormally directed into a peripheral pulmonary vein. This could be explained by an anomalous pulmonary venous return to the superior vena cava.

"Closing volume" during high-frequency ventilation in anesthetized dogs

Airway closure, mean airway pressure, gas exchange and different modes of artificial ventilation were investigated in anesthetized and paralyzed dogs with clinically healthy lungs. The animals were ventilated with either intermittent positive pressure ventilation (IPPV), continuous positive pressure ventilation (GPPV, positive end-expiratory pressure (PEEP) = 0.49 kPa) or high-frequency jet ventilation (HFJV, open system) of 2 and 30 Hz with an inspiratory to expiratory (I/E) - ratio of 30/70 and 60/40. Closing volume (CV) was determined by a modified technique, submitting the lung to constant subatmospheric pressure after an inspiratory vital capacity of oxygen. Two different tests for CV were used: the foreign gas bolus (FGB) with helium as nonresident gas and the single breath nitrogen dilution technique (SBO2). During conventional mechanical ventilation, CV decreased significantly (P less than 0.05) after establishing a PEEP of 0.49 kPa. During HFJV, CV increased significantly (P less than 0.01). This effect was predominantly dependent on I/E duration time ratio and to a lesser extent on ventilatory frequency. There were significant differences between CV obtained by the FGB-method (CV(helium] and CV derived from the SBO2-test (CV(SBO2], although both tests revealed the same proportional changes of CV during the different modes of ventilation. The elevated CV was associated with a decreasing Pao2 and increasing Aa-Do2 and Paco2, indicating substantial hypoventilation and mismatching of ventilation and perfusion. Mean airway pressure increased with both CPPV and HFJV, revealing a dissociation between airway pressure and regional FRC distribution during HFJV. It is concluded that certain modes of high-frequency ventilation lead to impaired distribution of inspired gas to dependent lung regions.(ABSTRACT TRUNCATED AT 250 WORDS)

Gravitropic bending of cress roots without contact between amyloplasts and complexes of endoplasmic reticulum

The polar arrangement of cell organelles in Lepidium root statocytes is persistently converted to a physical stratification during lateral centrifugation (the centrifugal force acts perpendicular to the root long axis) or by apically directed centrifugation combined with cytochalasin-treatment. Lateral centrifugation (10 min, 60 min at 10g or 50g) causes displacement of amyloplasts to the centrifugal anticlinal cell wall and shifting of the endoplasmic reticulum (ER) complex to the centripetal distal cell edge. After 60 min of lateral centrifugation at 10g or 50g all roots show a clear gravitropic curvature. The average angle of curvature is about 40 degrees and corresponds to that of roots stimulated gravitropically in the horizontal position at 1 g in spite of the fact that the gravistimulus is 10- or 50-fold higher. Apically directed centrifugation combined with cytochalasin B (25 micrograms ml-1) or cytochalasin D (2.5 micrograms ml-1) incubation yields statocytes with the amyloplasts sedimented close to the centrifugal periclinal cell wall and ER cisternae accumulated at the proximal cell pole. Gravitropic stimulation for 30 min in the horizontal position at 1 g and additional 3 h rotation on a clinostat result in gravicurvature of cytochalasin B-treated centrifuged (1 h at 50 g) roots, but because of retarded root growth the angle of curvature is lower than in control roots. Cytochalasin D-treatment during centrifugation (20 min at 50 g) does not affect either root growth or gravicurvature during 3 h horizontal exposure to 1-g relative to untreated roots. As lateral centrifugation enables only short-term contact between the amyloplasts and the distal ER complex at the onset of centrifugation and apically directed centrifugation combined with cytochalasin-treatment even exclude any contact the integrity of the distal cell pole need not necessarily be a prerequisite for graviperception in Lepidium root statocytes.

[ABS 800: expanding the possibilities of respiratory therapy]

A new module of the Dräger modular device system provides a means for demand CPAP (to increase FRC) and assisted spontaneous breathing. Both features together may largely increase the potency of ventilatory therapy for spontaneously breathing patients. The machine may reduce the need for full ventilatory support in acute respiratory failure, but also provides a valid and rational tool for respiratory therapy.

Viscoelasticity of tracheobronchial secretions in high-frequency ventilation

The effects of high-frequency ventilation (HFV) on the rheological properties of tracheobronchial secretions were investigated in vitro. The mucus was obtained by suction from 16 patients after major surgery of the larynx or hypopharynx. After short centrifugation, the mucus was treated with high-frequency vibrations of 3 or 30 Hz for 10 min in a chamber saturated with water vapor. The mucus was separated by a nonpermeable membrane from the ventilator's gas stream. Maximal, minimal, and mean viscosity were determined by a modified capillary viscosimeter. Under high-frequency vibrations, maximal, minimal, and mean viscosity slightly increased (p less than or equal to .001). Conversely, the mean viscosity of control samples did not change significantly. These findings indicate that high-frequency vibrations do not improve mucous rheology. Observed beneficial effects of HFV on mucociliary clearance may be caused by changes in the mucous subphase during HFV.