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G Putz

Publications and source records attributed to G Putz.

At least 37 records · Page 2Linked to original sources
PubMed1994

Evaluation of pressure-driven captive bubble surfactometer.

We modified the captive bubble surfactometer [S. Schürch et al. J. Appl. Physiol. 67: 2389-2396, 1989] to facilitate the measurement of surface adsorption rates and to simplify its construction. We used a range of standards and monolayers of dipalmitoylphosphatidylcholine to check the calibration of the device against measurements made in a Wilhelmy surface balance and in the captive bubble by using a cathetometer, and we found good agreement. As a further test we measured the surface properties of rabbit lavage lung surfactant (60,000 x average g for 60 min) at 1.0 mg phospholipid/ml. This material adsorbed within 1 s to near-equilibrium surface tension, reached surface tensions of < 5 mN/m on the second compression, and formed very stable films. We conclude that a captive bubble surfactometer can provide accurate information about important surface properties of lung surfactant films.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1994

Comparison of captive and pulsating bubble surfactometers with use of lung surfactants.

We compared surface tension measures of surfactants with various surface activities by using a pulsating bubble surfactometer (PBS) and a captive bubble surfactometer (CBS). Rabbit lung lavage surfactant (60,000 x average g for 60 min), bovine surfactant extract (Survanta), and a synthetic lipid surfactant mixture (dipalmitoylphosphatidylcholine-egg phosphatidylglycerol-palmitic acid) were studied at 1.25 mg phospholipid/ml. The PBS was used either unmodified according to manufacturer's instructions or with the sample chamber capillary kept dry and the sample adsorbing at maximum bubble size (5 min). The CBS was used in a manner that imitated the unmodified PBS. We found that all three techniques indicated low surface tension on the first cycle for 60K. For Survanta, the CBS and the modified PBS reported low surface tension on the first cycle, whereas the unmodified PBS did not achieve this within 10 cycles. For the synthetic lipid surfactant mixture, only the CBS measured low surface tension within 10 cycles. Video observations indicate that the modified PBS performs better than the unmodified PBS because keeping the capillary dry prevents surface film from occupying this large surface during cycling, thereby allowing larger area compressions.

Adsorption↗
PubMed1994

Surface activity of rabbit pulmonary surfactant subfractions at different concentrations in a captive bubble.

This study investigates the surface activity of rabbit pulmonary surfactant subfractions at different concentrations in a new pressure-driven captive bubble surfactometer, which provides more rigorous testing conditions than heretofore applied to this material. Subfractions were separated by centrifugation of lavage return into a third (P3; 1,000 x average g, 20 min), a fourth (P4; 60,000 x average g, 60 min), and a fifth (P5; 100,000 x average g, 16 h) pellet. At 2.0 mg phospholipid/ml, P3 and P4 demonstrated more rapid adsorption, lower minimum surface tensions on first and subsequent compressions, and lower monolayer compressibilities than did P5. This surface activity of P3 and P4 increased with concentration between 0.1 and 2.0 mg phospholipid/ml. Adsorption rate constants were approximately 10,000 times faster than desorption constants. We conclude that, in a normal lung, components of P3 and P4 determine alveolar surface tension. We speculate that under special circumstances even the less surface active P5 could have an important influence at the air-water interface.

Adsorption↗
PubMed1992

Tidal volume, breathing frequency, and oxygen consumption at different pressure support levels in the early stage of weaning in patients without chronic obstructive pulmonary disease.

The objective of this study was to evaluate the influence of different PSV levels on VT, F, VO2 in the early weaning phase of patients without chronic obstructive pulmonary disease. These parameters were tested for the predictive power for the success of the weaning. Patients on SIMV were studied during the first weaning attempt with PSV. Depending on their ventilatory support demands after 24 h they were divided into responders (patients breathing on CPAP) and nonresponders (patients being on a more invasive ventilatory mode). 14 ICU patients without pre-existing pulmonary disease being ventilated for at least 3 days entered the study. 2 of them could be studied a second time after failing the first weaning attempt. Beside the level of ventilatory support no other changes (drugs, nutrition) were allowed. VO2, VT, F were measured by a computer controlled, metabolic unit connected to the expiratory port of a Siemens Servo Ventilator. In addition, airway pressures, arterial pressure and heart rate were recorded. The measurements were performed at PSV of 5, 10 and 20 cmH2O. Arterial blood-gases were drawn at the end of each 60 min lasting PS period. Responders and nonresponders could be separated by the response of VO2, VT and F to a change in PS 10 to PS 20 cmH2O. Patients who significantly increased VT and significantly decreased F did not fulfil our weaning criteria. Our responders did not show a significant change in these two parameters, but a significant increase in VO2 at PS 20 cmH2O could be observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

High-frequency pulsation (HFP) in a patient with Guillain-Barré syndrome.

A patient with Guillain-Barré syndrome (GBS) developed a respiratory crisis despite recurrent treatment with plasma exchange. Thus mechanical ventilatory support became necessary. As an alternative to conventional ventilatory techniques high-frequency pulsation (HFP), a modified high-frequency jet-ventilation technique was used. According to the observations HFP may be a valuable technique for the continuous adaptation to the patient's individual respiratory demands in GBS.

Adult↗
PubMed1990

Gamma scintigraphic imaging of lung microvascular permeability in adult respiratory distress syndrome.

The sequence of lung microvascular permeability (LMVP) changes in early direct posttraumatic and late indirect pancreatitis-induced adult respiratory distress syndrome (ARDS) was studied and compared with that of a control group, as well as non-ARDS ICU patients. A computerized large field of view gamma camera was used to measure LMVP simultaneously over both lungs by In 113m-labeled transferrin and Tc 99m-labeled erythrocytes. The LMVP index (LMVPI) (%/h) was used to quantify LMVP in the dynamic scintigraphic measurement. In the control group the LMVPI was 2.6 +/- 2.8%/h for the right and 2.0 +/- 2.8%/h for the left lung. Similar values were found in mechanically ventilated ICU patients without ARDS (group A) on admission (right LMVPI 3.2 +/- 2.6, left LMVPI 2.6 +/- 2.7%/h) and 4 days later (right LMVPI 3.9 +/- 2.6, left LMVPI 2.3 +/- 1.8%/h). Interestingly, the initial evaluation of patients with direct early posttraumatic ARDS (lung contusion) (group B) showed significantly (p less than .01) elevated LMVP for the contused side (LMVPI 10.8 +/- 5.1%/h), but normal values for the nontraumatized lung (LMVPI 3.9 +/- 3.4%/h), whereas 4 days later the LMVP increased significantly (p less than .05) on the primarily healthy side (LMVPI 8.0 +/- 5.0%/h) while remaining elevated for the traumatized lung (LMVPI 10.9 +/- 6.0%/h).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[The course of extravascular lung water in severely injured patients in intensive care with and without thoracic trauma].

In patients with multiple injuries, the development of permeability edema can be assumed. However, no uniform shape of this fluid accumulation can be found even in the presence of severe injuries. Based on the first clinical observations, our aim was to search for correlations between the development of extravascular lung water (EVLW) and the individual injury pattern in severely traumatized ICU patients. PATIENTS and METHODS. Our investigations were performed in 48 artificially ventilated ICU patients. According to the prevailing injury pattern patients were divided into three groups: group A: 18 patients (mean age: 32 years, mean Injury Severity Score (ISS) = 29) with isolated thoracic trauma; group B: 10 patients (mean age: 27 years, mean ISS = 42) with severe multiple trauma but without any thoracic injury; group C: 20 patients (mean age: 33 years, mean ISS = 43) with severe multiple trauma and concomitant thoracic trauma. In all patients (group A, B, C), EVLW was determined by means of a double indicator method on a daily basis from the patient's admission to the ICU (day of trauma) until day 10. Additionally, the hemodynamic parameters (heart rate, mean arterial pressure, mean pulmonary arterial pressure, pulmonary capillary wedge pressure and cardiac index) were determined at the same time. RESULTS. As shown in Fig 1, EVLW was slightly elevated on day 1. However, on day 2 EVLW decreased within normal values and remained in that range until the end of the observation period. On day 3 a slight and fleeting increase of EVLW, but within normal range, can be seen. In group B (Fig.2), EVLW can be observed within normal range within a period of 4 days. Starting from day 5 until day 7 a marked increase (p greater than 0.01) in EVLW can be seen. From that maximum point EVLW development reverses slightly until day 10--however, without returning to the normal range. In group C, a marked biphasic pattern can be seen due to EVLW maximum values on post-traumatic days 3 and 7. However, in this group the EVLW was in the pathological range during the whole observation period. No statistically significant differences could be seen, when looking at hemodynamic variables. CONCLUSION. Isolated thoracic trauma will not lead to a marked pathological elevation of EVLW within the lungs. Moreover, EVLW decreases rapidly within a short time period. Based on our results, it seems that severe extrathoracic injuries will intensify microvascular injury in the initial period, as shown in our patients in group C. Increase of EVLW at a later time (day 7), as observed in groups B and C, is possibly the expression of a mediator and activator-induced "septiformal" injury of the microvascular endothelium. This may be caused by the underlying massive peripheral soft-tissue trauma. Specific elevations of EVLW subsequent to the individual injury pattern can indicate that that process has begun and is responsible for the origin of the microvascular injuries.

Adolescent↗
PubMed1989

Influence of high frequency ventilation at different end-expiratory lung volumes on the development of lung damage during lung lavage in rabbits.

The effects of high frequency ventilation in combination with sustained inflations was studied in the surfactant-deficient lungs of 18 New Zealand White rabbits (weight 1.9-2.1 kg) during anaesthesia with urethane and neuromuscular block with pancuronium. Lung damage was induced by repeated lung lavage. In nine rabbits (group I) baseline ventilator settings were maintained constant throughout the study and airway pressure was readjusted to achieve a constant tidal volume. In the other nine rabbits (group II), ventilation was reinstituted after lung lavage with one period of four sustained inflations followed immediately by high frequency ventilation. In group I there was a significant decrease in gas exchange for oxygen and deterioration in pulmonary mechanics, whereas in group II there was little change in baseline blood-gas values or pulmonary mechanics. These data suggest that, with adequate ventilatory management during the period of lung lavage, the lung damage produced by this manoeuvre may be obviated.

Anesthesia, Intravenous↗
PubMed1989

[The PEEP wave: an automated technic for bedside determination of the volume/pressure ratio in the lungs of ventilated patients].

The volume/pressure (V/P) ratio in the lungs has been reported to be useful in the adjustment of mechanical ventilation equipment to suit individual pulmonary mechanics. Most of the techniques used so far (e.g. the super-syringe technique) need an apneic period of approximately 60-120 s, in which the pulmonary gas volume is reduced by the continuing oxygen uptake. Thus, a bias of 200-400 ml in volume is superimposed on the record. In contrast to the super-syringe technique, a new automatic procedure has been developed for which no apneic period is needed. This technique is called the PEEP wave technique: it is based on the imbalance between inspiratory and expiratory volumes after a sudden change in PEEP. The software of a Dräger Evita respirator was adapted to allow automatic application of a special sequence of respiratory cycles with stepwise increase and decreases in PEEP between two preselectable borderline levels. The equipment is switched to the next PEEP level when the difference between two consecutive expiratory tidal volumes is less than 15 ml. After the highest level of PEEP is reached the procedure is reversed until PEEP returns to its initial value. Constant inspiratory tidal volumes (Vti) are achieved by a high pressure servo valve (HPSV) under conditions of chocked flow, resulting in inspiratory tidal volumes which are independent of back-pressure. Thus, only the difference in expiratory tidal volumes (Vte) before and after a PEEP change is necessary to determine gain and loss in lung volume (delta FRC).(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1989

[Biphasic positive airway pressure (BIPAP)--a new form of augmented ventilation].

Two modes of combining spontaneous breathing and mechanical ventilation are already in use: periodic mechanical support always followed by a period of spontaneous breathing (intermittent mandatory ventilation; IMV) and mechanical support of each spontaneous breath (inspiratory assistance; IA). Biphasic positive airway pressure (BIPAP), in contrast, is based on neither of the above mentioned principles. It is rather a mixture of pressure controlled (PC) ventilation and spontaneous breathing, which is unrestricted in each phase of the respiratory cycle. The BIPAP circuit switches between a high (Phi) and a low (Plo) airway pressure level in an adjustable time sequence. At both pressure levels the patient can breathe spontaneously in a continuous positive airway pressure system (CPAP). The volume displacement caused by the difference between Phi and Plo and the BIPAP frequency (F) contribute the mechanical ventilation to total ventilation. Duration of the Phi and the Plo phases can be independently adjusted. Similar to the I:E ratio during controlled ventilation, the phase time ratio (PhTR) is calculated as the ratio between the durations of the two pressure phases. A PhTR greater than 1:1 is called IR-BIPAP. A BIPAP system can be set up either as a continuous flow system, or as a demand valve system. A continuous-flow BIPAP system consists of a high-flow CPAP system, a reservoir bag, and a pneumatically controlled membrane valve in the expiratory limb. A magnetic valve operated by an impulse generator switches between Phi and Plo, controlling the pop-off pressures of the expiratory valve.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1989

[The use of a transcutaneous pO2/pCO2 combination electrode during volume therapy in a child in shock].

We report a 1-year-old boy in hemorrhagic shock due to a large subgaleatic hematoma following severe head trauma (blood pressure (BP) 30/15 mmHg; heart rate (HR) 110; Hb 45 g/l; arterial pH 7.16; BE-20 mEq/l). The child was intubated and ventilated; initial FIO2 was 0.9. In an attempt to monitor the cardiovascular system noninvasively a transcutaneous oxygen/carbon dioxide combielectrode was placed on the chest. Initially we observed a large difference between arterial pO2 (paO2 = 166 mmHg) and transcutaneous pO2 (tcpO2 = 7 mmHg) and arterial pCO2 (paCO2 = 16 mmHg) and transcutaneous pCO2 (tcpCO2 = 55 mmHg), reflecting poor skin perfusion and severe tissue acidosis. Under aggressive volume replacement tcpO2 rose along with BP and tcpCO2 returned to near arterial values. Even after stabilization of gross hemodynamic parameters such as HR and BP and despite reductions in FIO2, tcpO2 continued to increase with further volume replacement, reflecting an existing volume deficit.

Blood Gas Monitoring, Transcutaneous↗
PubMed1988

[High frequency ventilation with a conventional respiratory following heart surgery interventions].

This study was designed to compare the effects of Continuous Positive-Pressure Ventilation (CPPV) and, by using the same unmodified conventional ventilator, High-Frequency Positive-Pressure Ventilation (HFPPVkonv). First, CPPV and HFPPVkonv were studied in a lung model with both normal (R = 5 mbar/1/second) and elevated (R = 20 mbar/1/second) resistance. Our results indicate that in HFPPVkonv the large compressible volume of the conventional ventilator did not influence lung model ventilation at normal resistance. The adjusted (300 ml) tidal volume (VT) and the measured volume of actual expiration (270 ml) were about the same (Fig. 1). However, with elevated resistance air trapping occurred. The large compressible volume influenced model ventilation during both CPPV and HFPPVkonv (Fig. 2). As a second step we evaluated the effects of HFPPVkonv on gas exchange, airway pressure, and hemodynamics in 12 patients (aged 43-69) postoperatively after elective cardiac surgery. After a period of stabilization at the intensive care unit every patient was first ventilated with CPPV. The ventilator settings were: VT = 10-12 ml/kg, inspiratory: expiratory ratio (I:E) = 1:2, frequency (F) = 12/min, V = 60 1/min, PEEP = 5 cm, FiO2 = 40%. After 20 min of CPPV baseline measurements were made (series I). Then the initial ventilator settings of CPPV were switched to HFPPVkonv, the conventional ventilator remaining unmodified. The settings were changed as follows: I:E = 1:3, F = 60/min, V = 120 1/min, PEEP = 5 cm, FiO2 = 40%. During 60 min of HFPPVkonv variables were measured first after 20 min (series II) and again after another 40 min (series III). Minute volume had to be doubled after changing from CPPV to HPFFVkonv to achieve eucapnia. As a result of the new ventilatory settings, VT and hold showed a significant decrease (P less than 0.01) (Table 2).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Treatment of re-expansion edema ('unilateral ARDS") after rapid pneumothorax drainage].

A rare complication after delayed re-expansion of pneumothorax is reported. A polytraumatized patient with stable vital functions was admitted to our ICU immediately after surgery. Later, oxygenation worsened treated by a rise in FiO2. Concomitant tachycardia was thought to be due to increasing body temperature. On day 3 of treatment in the ICU further deterioration in gas exchange (and in hemodynamics, with complete collapse of the left lung) was diagnosed on X-ray examination. Retrospectively, the development of this condition could be traced on the X-ray films taken during the previous 3 days. Thoracic drainage and suction resulted in complete re-expansion of the lung. After re-expansion worsening of gas exchange and unilateral ARDS-like configurations were observed on chest X-ray. Reversal of the I:E ration and a rise in PEEP improved gas exchange and the X-ray appearance immediately. In the next few days the intensity of the respiratory treatment could be reduced, and after a short period of CPAP the patient was discharged from the ICU. Three mechanisms for development of this "unilateral ARDS" are discussed: loss and suppressed regeneration of surfactant in prolonged atelectic alveolar compartments; increased capillary fluid escape due to suction; and increased complement activation and reduced degradation of edematogenic bradykinin in hypoxic alveolar compartments. Possible clinical implications for the treatment of longer duration pneumothorax are: fractionated drainage and respirator settings, reopening collapsed alveoli in an inhomogeneously diseased lung such as IRV.

Adult↗
PubMed1986

[How much reintegration can be achieved in patients after severe craniocerebral injury?].

152 patients, who had suffered head and brain injury during the years 1980 to 1982 were interviewed by letter using a standardized questionnaire to assess the individual outcome. There were questions concerning activities of daily life, invalidity, work activities, social relationships with family and other persons, leisure activity and the grade of persisting sequelae. There were 106 replies, 16 patients had died meanwhile. According to their neurological symptoms on admission at the intensive care unit the patients were divided into two groups. Group I included patient, who showed symptoms of midbrain syndrome stage 1 and 2, while group II presented patients had midbrain syndrome stage 3 and 4. Activities of daily life (feeding, dressing, toiletting and ability to get out of bed and move around the room) were restored in the great majority of patients. 15 patients of group II were classified as invalid. Significant changes in social relationships with the family were seen in 50% of the patients. Further, a decrease of contacts with friends, and a significant decrease in leisure activity (sport) was noted. 28.4% of the patients of group I and 36.8% of the patients of group II, who were at work before the trauma, now were out of work. The others generally worked below their previous level. Persisting sequelae included headache, lack of concentration and weakness of extremities. These symptoms were more prominent in the patients of group II; surprisingly little complaints concerned sexual life and somatic problems. It was found, that severe head and brain injury had significantly changed the patient's life in most cases. Work activities were strongly impaired in about 30% of cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗