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R Fretschner

Publications and source records attributed to R Fretschner.

At least 19 recordsLinked to original sources
PubMed2004

Influence of underlying disease on the outcome of critically ill patients with acute renal failure.

BACKGROUND AND OBJECTIVE: The development of acute renal failure (ARF) in critically ill patients is associated with an increase in hospital mortality. Recently, it was shown that starting renal replacement therapy early and using high-filtrate flow rates can improve the outcome, but this could not be confirmed in later investigations. Studying selected patient subgroups could provide a useful basis for patient selection in future trials evaluating the outcome of renal replacement therapies. We, therefore, investigated the impact of the underlying disease on the outcome of patients with ARF. METHODS: We retrospectively analysed 306 patients with ARF who were treated with renal replacement therapy. Patients were classified according to six initial diagnosis groups: haemorrhagic shock, post-cardiac surgery, post-liver transplantation, trauma, severe sepsis and miscellaneous. Univariate and multivariate multiple logistic regression analysis was used to determine which factors influenced the outcome. RESULTS: Underlying disease proved to be the only independent risk factor for mortality that was present at intensive care unit (ICU) admission (P = 0.047). Patients with severe sepsis had a significantly higher mortality rate (68%) than ARF patients as a whole (51%) (P = 0.02). Length of stay in the ICU, the use of catecholamines, the delay before ARF onset, and the correlation between APACHE II score and ICU length of stay proved to be additional independent predictors of outcome. CONCLUSIONS: Patient selection and subgroup definition according to the underlying disease could augment the usefulness of future trials evaluating the outcome of ARF.

Acute Kidney Injury↗
PubMed2003

[Noninvasive determination of cardiac output in ventilated patients . Clinical evaluation of a simplified quick method].

OBJECTIVE: This study was performed to evaluate a new simplified rebreathing method to determine cardiac output (CO) in mechanically ventilated patients. METHODS: Using a rebreathing system (AMIS 2001, Innovision, Dänemark), effective pulmonary blood flow (PBF) and oxygen consumption (V(radical)O2) were determined non-invasively in 40 patients. After estimation of arterial (CaO2) and capillary oxygen (CcO2) content from the results of an arterial blood gas analysis, intrapulmonary shunt was calculated as Q(s)/Q(t) = [CcO2CaO2] * PBF/V(radical)O(2). Cardiac output was determined by the rebreathing method as CO(rb) = PBF/(1- Q(s)/Q(t)). The cardiac output measured by thermodilution (CO(thd)) was used to determine reference values, which were calculated as mean value of CO(thd) and CO(rb). Intrapulmonary shunt calculated from arterial and mixed-venous blood gas analyses served as reference for the non-invasive determination. In addition, reproducibility of the new method was determined in 15 patients. RESULTS: CO(thd) varied from 3.7-9.5 l/min (6.1 +/- 1.6 l/min; mean +/-SD). Bias and precision of CO(rb) determination accounted for 0.18 l/min (2.9%) and +/- 0.61 l/min (10%), respectively. Precision of intrapulmonary shunt measurement accounted for +/-2.1%. Reproducibility of the CO measurements accounted for 0.24 l/min or 3.9%. CONCLUSION: The rebreathing system evaluated in the present study allows the noninvasive determination of cardiac output with rather high accuracy and good reproducibility. However, technical improvement and further investigation in patients with extremely high cardiac output and shunt values will be needed before its routine clinical use.

Aged↗
PubMed2001

Patient data management systems in critical care.

Electronic patient data management systems (PDMS) were clinically used for the first time in the 1970s. Their purpose was to automatically document vital parameters sampled by monitors and to replace handwritten medical files. Because of the continuous development of computer technology, however, demands on PDMS have increased immensely. PDMS are currently expected to assist clinicians at every level of intensive care, i.e., at the strategic level of physicians' orders and prescriptions, at the operational level, and at the administrative level. In 1994, a PDMS (CareVue; Agilent Technologies) was installed and further developed in the anesthesiologic intensive care unit of the university hospital in Tübingen. The goals of this article were to describe the current demands on PDMS, to communicate our experiences in implementing a PDMS, to list the costs of purchasing and maintaining the system, and to report on the acceptance among physicians and nursing personnel. This article may assist new users in planning for, purchasing, and implementing a PDMS.

Costs and Cost Analysis↗
PubMed1999

Implementation of an interactive computer-assisted infection monitoring program at the bedside.

A new computer-assisted infection monitoring (CAI) software program has been developed for use in an intensive-care unit (ICU). By means of an interactive dialogue with physicians at the bedside, infection diagnoses and therapeutic decisions were recorded prospectively during a 3-month test period. By linking epidemiological data with information about therapeutic decisions, CAI could assess the quality of the therapeutic decisions. Antibiotics chosen empirically before the availability of any culture results, matched the antibiotic susceptibility patterns of the subsequently identified pathogens in 74% of the cases. Therapy chosen in collaboration with the computer after the pathogen was known, but before sensitivity results were available, corresponded with the eventual antibiograms of the microorganisms in 90% of the cases. Data analysis by CAI allowed us to assess critically the diagnostic and therapeutic habits in our ICU. Using the query-by-example method, CAI automatically calculated device-associated infection rates.

Adolescent↗
PubMed1996

New aspects of pulmonary mechanics: "slowly" distensible compartments of the respiratory system, identified by a PEEP step maneuver.

OBJECTIVE: The aims of the present study were 1) to evaluate a method for identification of "slowly" distensible compartments of the respiratory system (rs), which are characterized by long mechanical time constants (RC) and 2) to identify "slowly" distensible rs-compartments in mechanically ventilated patients. DESIGN: Prospective study on a physical lung model. SETTING: Intensive Care Unit, University Hospital, Tübingen. PATIENTS AND PARTICIPANTS: 19 patients with severe lung injury (acute respiratory distress syndrome, ARDS) and on 10 patients with mild lung injury. MEASUREMENTS AND RESULTS: Positive end-expiratory pressure (PEEP)-increasing and -decreasing steps of about 5 cmH2O were applied and the breath-by-breath differences of inspiratory and expiratory volumes (delta V) were measured. The sequence of delta Vs were analyzed in terms of volume change in the "fast" compartment (Vfast), the "slow" compartment (Vslow), total change in lung volume (delta VL) and mechanical time constant of the slow compartment (RCslow). Thirty-eight measurements in a lung model revealed a good correlation between the preset Vslow/delta VL and Vslow/delta VL measured: r2 = 0.91. The Vslow/delta VL measured amounted to 0.94 +/- 0.15 of Vslow/delta VL in the lung model. RCslow measured was 0.92 +/- 0.43 of the RCslow reference. Starting from a PEEP level of 11 cmH2O PEEP-increasing and PEEP-decreasing steps were applied to the mechanically ventilated patients. Three out of ten patients with mild lung injury (30%) and 7/19 patients with ARDS (36.8%) revealed "slowly" distensible rs-compartments in a PEEP-increasing step, whereas 15/19 ARDS patients and 1/10 patients with mild lung injury showed "slowly" distensible rs-compartments in a PEEP-decreasing step (78.9% vs 10%, P < 0.002, chi-square test). CONCLUSIONS: The gas distribution properties of the respiratory system can be easily studied by a PEEP-step maneuver. The relative contribution of the "slow" units to the total increase of lung volume following a PEEP step could be adequately assessed. "Slowly" distensible rs-compartments could be detected in patients with severe and mild lung injury, however significantly more ARDS patients revealed "slow" rs-compartments in PEEP-decreasing steps. The influence of "slowly" distensible rs-compartments on pulmonary gas exchange is unknown and has yet to be studied.

Adult↗
PubMed1993

A simple method to estimate functional residual capacity in mechanically ventilated patients.

OBJECTIVE: The aim of the present study was to evaluate a simplified method for FRC measurement. DESIGN: Accuracy and precision of the method were assessed in a physical lung model; reproducibility was tested in 10 mechanically ventilated patients. In each patient FRC was measured at three PEEP levels. SETTING: Post-operative intensive care unit in a university hospital. MEASUREMENTS AND RESULTS: Gas flow, CO2 concentration, and O2 concentration were measured during in- and expiration by pneumotachography, a mainstream capnometer and a sidestream O2-analyser. For FRC-measurement inspiratory O2 concentration was changed by 30%. FRC was determined as mean value of a N2 washout and N2 washin procedure. Evaluation of this method in a lung model shows a good correlation between FRC set in the lung model and FRC measured (FRC measured = 1.028*FRG model + 22.92 ml; r2 = 0.957; n = 30). The mean difference was 4.4% of FRC-reference (range -8.4% to +21.7%). Duplicate determinations in 10 mechanically ventilated patients differed by an average of -2.7% (range -30.1% to +27.3%). CONCLUSION: Our results suggest that the proposed method can be used in daily clinical work.

Acute Disease↗
PubMed1993

[First aid and prognosis following drowning accidents. Results of a retrospective study of 115 cases].

OBJECTIVE AND STUDY DESIGN: In 115 cases of submersion the initial findings of the rescue team, the patients status in the emergency room and the course of clinical treatment were analyzed retrospectively. RESULTS: Submersion accidents happened preferably in February, March and in the summertime from May to August. Most of the accidents took place in public waters or public baths (85.2%). Children below 10 years of age were involved in 34.8% of the submersion accidents. 57 patients were near drowned and 58 patients were drowned. The prognosis of patients with detectable heartbeat at the site of the accident depends on the primary pulmonary lesion. If respiratory insufficiency is recognized early and treated aggressively by intubation and mechanical ventilation with PEEP, these patients have an excellent prognosis. Only one patient with detectable heartbeat died, typically, after delayed treatment of respiratory failure. 55 patients recovered completely; one patient was suffering from a lesion of the n. medianus. Contrariwise, the prognosis of patients without detectable heartbeat is mainly determined by the consequences of hypoxaemia and is, overall, poor. Though resuscitation succeeds in 50% of submersion victims, only one out of four successfully resuscitated patients survived with little or no neurologic damage. Severe hypothermia may improve the prognosis of submersion victims. CONCLUSION: Thus, there are no useful parameters that would accurately predict the individual course of a submersion victim.

Adolescent↗
PubMed1993

Pulmonary venodilation by isoflurane improves gas exchange during Escherichia coli bacteremia.

OBJECTIVE: To determine how isoflurance affects the longitudinal distribution of pulmonary vascular resistance and pulmonary gas exchange during Escherichia coli bacteremia. DESIGN: Prospective, controlled study with open-label assignment of animals to two groups. SETTING: Laboratory. SUBJECTS: Goehingen minipigs. INTERVENTIONS: Induction of acute respiratory failure by a 4-hr infusion of live E. coli bacteria in 12 animals; six animals anesthetized with methohexital/piritramide; six animals anesthetized with isoflurane. The control group consisted of four animals that received the same surgical procedure, but no E. coli infusion. Two animals were anesthetized with methohexital/piritramide and two with isoflurane, respectively. MEASUREMENTS AND MAIN RESULTS: Cardiac output and pressures were measured by means of an arterial catheter, Swan-Ganz catheter, and a left atrial catheter. Effective pulmonary capillary pressure was evaluated graphically from a pulmonary artery occlusion pressure decay. Arterial-alveolar PO2 ratio was calculated to evaluate pulmonary function. Measurements were performed before and after 1, 2, and 3.5 hrs of E. coli infusion. Statistical significance was tested with analysis of variance (ANOVA). E. coli infusion caused hypodynamic shock, an increase in pre- and postcapillary pulmonary vascular resistance and respiratory failure. Postcapillary pressure gradient and effective pulmonary capillary pressure were lower in the isoflurane-group. Methohexital-anesthetized animals developed pulmonary dysfunction after 1 hr of bacteremia, whereas isoflurane-anesthetized animals developed pulmonary dysfunction after 3.5 hrs of E. coli infusion (significantly different, ANOVA, p < .05). There were no significant changes in the sham group. CONCLUSIONS: Isoflurane is a pulmonary venodilator. During lethal E. coli infusion, it ameliorates the increase in pulmonary capillary pressure and preserves pulmonary function until vascular permeability increases.

Administration, Inhalation↗
PubMed1993

[Longitudinal distribution of pulmonary vascular resistance in patients with acute respiratory insufficiency].

Effective pulmonary capillary pressure (Pc) is a major factor determining transvascular fluid filtration in the lung. It may easily be estimated from the pressure decay after rapid pulmonary artery occlusion. If Pc is known, the longitudinal distribution of pulmonary vascular resistance (PVR) can be evaluated. The present study was performed to address the following questions: (a) whether the severity of acute lung injury influences Pc and the longitudinal distribution of PVR; and (b) whether pulmonary artery occlusion (PAOP) or wedge pressure represents effective Pc during acute respiratory failure. PATIENTS AND METHODS. The investigation was performed in 45 mechanically ventilated patients. According to Murray's criteria 13 patients showed no lung injury, 19 had mild to moderate lung injury, and 13 had severe lung injury (adult respiratory distress syndrome, ARDS). As described by Holloway, effective Pc was evaluated from the pressure decay after rapid occlusion of the pulmonary artery (Figs. 1 and 2). The precapillary pressure gradient was determined as the difference between mean pulmonary artery pressure and Pc, the postcapillary pressure gradient as the difference between Pc and PAOP. Three measurements were performed and Pc determined as their mean value. The Kruskal-Wallis test and Mann-Whitney U test were performed to check statistically significant differences between groups. A Bonferroni correction was performed for multiple testing; P < 0.05 was accepted. RESULTS. Effective Pc was significantly different between patients with severe lung injury (20 +/- 3 mm Hg) and patients with mild to moderate lung injury (16 +/- 3 mm Hg), and between the latter group and patients without lung injury (12 +/- 3 mm Hg). The postcapillary pressure gradient and the relative amount of pulmonary venous vascular resistance, as well, were significantly influenced by the severity of the lung injury. In patients with ARDS the postcapillary pressure gradient was 4 +/- 1 mm Hg, whereas in patients with mild to moderate and without lung injury the postcapillary pressure gradients were 3 +/- 1 mm Hg and 2 +/- 1 mm Hg, respectively. Two ARDS patients had a postcapillary pressure gradient of 7 mm Hg (Pc 22 mm Hg and 19 mm Hg, PAOP 15 mm Hg and 12 mm Hg). One patient with severe lung injury had a postcapillary pressure gradient of 9 mm Hg (Pc 22 mm Hg, PAOP 13 mm Hg). In patients with severe lung injury 28 +/- 7% of the PVR was located in the postcapillary vascular system, whereas in patients with mild to moderate and without lung injury 22 +/- 7% and 16 +/- 6% of PVR was located in the pulmonary venous system. CONCLUSIONS. The longitudinal distribution of PVR is influenced by the severity of lung injury. PAOP, therefore, may not represent changes in Pc in patients with acute respiratory failure. The routine use of Pc measurement, however, can not be recommended until it has proven more useful than determination of PAOP when managing critically ill patients.

Acute Disease↗
PubMed1992

[Amrinone for cardiovascular therapy in hypodynamic septic patients?].

Pulmonary hypertension, systemic vasodilation and the supply dependency of oxygen uptake are the major problems associated with sepsis. Thus, the goal of haemodynamic therapy in septic patients is an increase in cardiac output large enough to permit adequate tissue oxygenation. The purpose of this study was to establish whether the additional use of the phosphodiesterase inhibitor amrinone is useful in hypodynamic septic patients with inadequate tissue perfusion. Nine patients who had developed the clinical signs of sepsis (temperature greater than 38.5 degrees C, leukocytosis greater than 15,000/mm3, thrombopenia less than 100,000/mm3 or a drop in platelet count greater than 30%, cardiovascular shock) were given amrinone 30 micrograms.kg-1.min-1 for one hour. All patients showed mixed venous oxygen saturations below 70% and oxygen extraction rates above 30%, despite maximum catecholamine therapy. Haemodynamic parameters were measured with the help of a pulmonary artery catheter. Statistical significance was checked using the Wilcoxon signed-ranks test. During amrinone application cardiac index increased significantly from 4.6.1.81.min-1.m-2 to 5.6 +/- 1.81.min-1.m-2 (p less than 0.01), while central venous pressure was kept constant by volume supply. Mean pulmonary artery pressure remained nearly unchanged, whereas mean arterial pressure dropped significantly from 91 +/- 13 mmHg to 75 +/- 8 mmHg (p less than 0.01). The oxygen supply rose during administration of amrinone by an average of 17%, which led to a rise in oxygen uptake. Independence of oxygen uptake from oxygen supply, however, could not be attained. In septic patients, amrinone increases cardiac output via pulmonary vasodilation. However, pronounced systemic vasodilation lowers arterial blood pressure, enhancing the risk of myocardial ischaemia.

Aged↗
PubMed1992

[Capnometry in pediatric anesthesia. The effect of the measurement site and respiratory rate].

OBJECTIVE: To evaluate the influences of site of measurement, respiratory rate, and tidal volume on end-tidal PCO2 measurement in children ventilated with a non-rebreathing system. SETTING: Paediatric surgical patients of a university hospital. PATIENTS: Thirty-one children scheduled for major abdominal or urogenital surgery; weight varying between 2.2 and 9.8 kg. INTERVENTIONS AND METHODS: During a relative steady-state situation, end-tidal carbon dioxide partial pressure (PetCO2) was measured at the proximal and distal ends of the endotracheal tube by a sidestream analyser (Datex, Normocap) and between the proximal end of the tube and the Y-piece of the ventilator by a mainstream analyser (Hewlett Packard, HP14265A). PetCO2 was corrected for water vapor and calculated as partial pressure at a barometric pressure of 760 mmHg. At the same time, capillary blood was taken for blood gas analysis. The capillary-end-tidal PCO2 gradient [dPCO2(cap-et)] was computed to compare the three capnometric methods. Statistical analysis was performed with the Friedmann test. Correlations were calculated by means of the least-square fitting method and significance of the correlation was checked with the F-test. RESULTS: dPCO2 (cap-et) did not differ significantly in children with more than 6 kg body weight. In patients less than 6 kg, however, the three capnometric methods revealed significantly different dPCO2 (cap-et) values (P less than 0.01): dPCO2 (cap-et) was 3.0 +/- 4.7 mmHg at the distal end of the endotracheal tube, 5.8 +/- 4.6 mmHg at the proximal end, and 8.7 +/- 4.6 mmHg between the proximal sidestream connector and the Y-piece of the ventilator. There was no correlation between tidal volume and dPCO2 (cap-et) (Fig. 1), however, a significant relation was found between respiratory rate and dPCO2 (cap-et) (Fig. 2) and between respiratory rate and the PCO2 difference between the distal and proximal ends of the endotracheal tube (Fig. 3). CONCLUSIONS: Even in a non-rebreathing system, capnometry is influenced by the site of measurement. In small children with body weight below 6 kg, analysis of an endotracheal sample may provide the best PetCO2 values. In our opinion, dPCO2 (cap-et) in the present investigation was not caused by rebreathing or by pendelluft (a significant correlation between dPCO2 (cap-et) and tidal volume would then have been expected), but was mainly due to ventilation-perfusion mismatch. This may result from high respiratory rates causing inadequate ventilation of lung regions with long time-constants.

Carbon Dioxide↗
PubMed1991

[Risk indicators in coronary surgery].

We examined the perioperative course of 1013 patients who had undergone coronary surgery between 1984 and 1987, to identify preoperative examination findings which are suitable as risk indicators in coronary surgery. The features we paid attention to were: anamnestic data, parameters of coronary disease, haemodynamic parameters and accompanying illnesses. We considered a perioperative course as complicated when systolic blood pressure dropped to 80 mmHg or less for longer than 15 min, when reconnection to the heart-lung-machine was necessary, when an intra-aortal balloon counterpulsation was required, when the patient had to have mechanical ventilation for longer than 24 h, when resuscitation took place, or when the patient died in the hospital. The Chi-square test was used for statistical analysis. Very good risk indicators (p less than 0.001) were: age greater than 60 y, resuscitation history, more than two bypass grafts, SvO2 70%, ejection fraction less than 50% and cardiac index less than 2.5 l/min*m2. Good risk indicators (p less than 0.001) were: functional capacity less than 50 watts, more than one previous myocardial infarction and LVEDP greater than 20 mmHg. LCA-stenosis, arterial hypertension with diastolic blood pressure values above 100 mmHg, and obstructive airway disease were identified as suitable risk indicators (p less than 0.05). The following findings were combined with significantly increased mortality: female sex, age over 60 years, two or more previous myocardial infarctions, history of resuscitation, mixed venous oxygen saturation below 70% and the need for three or more bypass grafts for complete revascularisation.

Adult↗