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Biomedical subjects

H Lennartz

Publications and source records attributed to H Lennartz.

At least 19 recordsLinked to original sources
PubMed1992

Evaluation and first validation study on a simplified drug dosage algorithm for multiple organ failure patients.

As reported previously, drug concentrations during continuous hemofiltration (HF) and extracorporeal lung assist (ELA) follow certain rules, which can be expressed by a simplified algorithm for dosage adjustment: Drug sieving (S, fu) depends on the protein free fraction with small limitations, while the extrarenal elimination rate is not a constant but correlates inversely with the clinical state, r = -0.34, p = 0.00067, n = 96. Up to now, more than 218 cases of drug dosage adjustments have been performed, following the described regimen: The expected concentration is obtained in 79-84% already from the first estimation for drugs such as aminoglycosides, vancomycin, teicoplanin, beta-lactam antibiotics, heart glycosides, and theophylline. Skilled therapeutic drug monitoring (TDM) with elaborated pharmacokinetic programs fails to improve these results significantly. Nevertheless, sporadic TDM is essential in these patients according to their rapidly changing clinical states.

Acute Kidney Injury↗
PubMed1992

Progress in veno-venous long-term bypass techniques for the treatment of ARDS. Controlled clinical trial with the heparin-coated bypass circuit.

Extracorporeal CO2 removal combined with low-frequency positive pressure ventilation (ECCO2-R LFPPV) is a new therapeutic approach in treatment of ARDS. The main problem during long-term extracorporeal support is anticoagulation and related bleeding problems. We conducted a prospective, randomized and controlled clinical trial in 18 patients to compare the effect of the non-heparin-coated (Scimed = group 1) with the heparin-coated (Carmeda = group 2) extracorporeal circuit on clinical course and complication rate. In group 2 the daily blood loss, the amount of substituted red cells and the i.v. heparin dose were significantly lower than in group 1. Bleeding complications were less and more patients survived in group 2. The disadvantage of the hollow fiber oxygenators in the heparin-coated system was plasma leakage, which was more frequent in patients with pancreatitis and hyperbilirubinemia.

Adolescent↗
PubMed1991

[The importance of Pneumocystis carinii infection in patients with acute respiratory distress syndrome].

Each year we treated approximately 40 patients with adult respiratory distress syndrome (ARDS) in our department of anaesthesiology. In these cases we found with bronchoalveolar lavage followed by microbiological examination, a high incidence (40 per cent) of pneumocystis carinii contamination. An infection with Pneumocystis carinii deteriorates the clinical course of ARDS. Effective drugs were the combination of trimethoprim and sulfamethoxazole. Under this therapy we always saw a decrease of infiltrations in the chest-x-ray as well as an improved gas exchange. No relapse was seen in any case.

Adolescent↗
PubMed1991

[Determinations by indirect calorimetry need not be expensive and technically complicated. A new measurement system and its validation].

Presentation of a newly conceived measuring instrument to determine the energy expenditure of critically ill patients at the bedside by means of indirect calorimetry. The special advantages of the measuring instruments are easy handling, little maintenance and very low working expenses and prime costs. The accuracy of measurement is considerable nd is comparable with that of other measuring methods, as has been established by an extensive validation.

Calorimetry, Indirect↗
PubMed1991

The prognostic value of extracellular matrix component concentrations in serum during treatment of adult respiratory distress syndrome with extracorporeal CO2 removal.

The time-dependent concentrations of hyaluronan, aminoterminal propeptide of type III procollagen, and laminin were determined in sera of 16 patients with severe adult respiratory distress syndrome during treatment with an extracorporeal CO2 removal device. Patients were classified according to lung parameters as responders (n = 10) and non-responders (n = 6) to extracorporeal CO2 removal. At the beginning of treatment strongly elevated serum concentrations of all studied extracellular matrix components were found. During the first 6-11 days of treatment the concentrations of aminoterminal propeptide of type III procollagen and hyaluronan increased further in non-responders but decreased in the majority of responders, while laminin decreased in both groups. No significant correlations were found between the serum concentrations of connective tissue components and the parameters of lung function. By non-parametric analysis of variance, significant differences between responders and non-responders according to treatment time could be established. By analysing the time course of the serum concentrations of hyaluronan and aminoterminal propeptide of type III procollagen, a total differentiation between responders and nonresponders was made possible by the trends of these analytes as early as three days after the start of treatment. The determination of aminoterminal propeptide of type III procollagen and hyaluronan in serum of patients with adult respiratory distress syndrome might therefore have prognostic significance in extracorporeal CO2 removal.

Adolescent↗
PubMed1991

[Drugs in the intensive care unit--need for dosage adjustment in organ failure].

Drug dosage in intensive care patients is a common problem that cannot be sufficiently solved in practice. To obtain an idea as to the variance of multiorgan failure during treatment, the pharmacokinetics of 17 drugs were evaluated in 96 patients. Continuous hemofiltration served as a model for constant elimination rates. In addition, the elimination of drugs was investigated during extracorporeal lung support. For 11 of 15 drugs on which kinetic studies had been completed, dose reductions had to be performed. Furthermore, widespread variance in their volume of distribution and their clearance and in the extrarenal fraction of elimination were detected. The latter showed a close correlation to clinical scores of illness. This led us to develop a new algorithm for primary estimations of drug dosage during hemofiltration. In a preliminary validation study, the algorithm seemed to show an improvement in the drug dosage in these populations. Nevertheless, a more simplified means of monitoring therapeutic drugs should be continued, especially for toxic agents.

Critical Care↗
PubMed1991

[Infection-induced change in the pharmacokinetics of cefotaxime. Dose calculation in multiple organ failure and relevance of score systems].

The pharmacokinetics of cefotaxime were investigated in 14 patients suffering from multiple-organ failure requiring pump-assisted, continuous volume-constant hemofiltration (CVHF) for blood purification, whereby the filtration rate was 20 ml/min. Samples of blood and ultrafiltrate were evaluated by high-pressure liquid chromatography. For dose adjustment, three different algorithms of Dettli and Kroh were used. As compared with values obtained for anuric patients during the dialysis-free period, the mean serum half-life was nearly doubled (2.75 vs 4.48 h). This reduced elimination depended mainly on a diminished non-renal elimination ratio ranging from 0.085 to 0.366. The volume of distribution remained unchanged within a wide interindividual range (Vz, 0.35 l/kg, from 0.22 to 0.56 l/kg); the sieving coefficient increased to 0.89 as compared with 0.62 in healthy volunteers. Dose adjustment by algorithms showed varied degrees of over-dosage. The estimate closest to an optimal dose was reached by the application of a new algorithm of Kroh (mean dose deviation +19%; SD, +/- 27%) using an individual non-renal elimination ratio (QIND). QIND correlated significantly with the severity of disease according to the sepsis score of Elebute and Stoner (r = 0.763, P less than 0.005). Thus, it is possible to adjust reliably individual dosage in multiple-organ failure and to reduce the frequency of drug monitoring required.

Adult↗
PubMed1990

Extracorporeal gas exchange in adult respiratory distress syndrome: associated morbidity and its surgical treatment.

Extracorporeal carbon dioxide removal (ECCO2-R) over a membrane lung is a new therapy for patients with adult respiratory distress syndrome (ARDS) who frequently suffer from lung complications caused by long-term artificial ventilation and who may require major thoracic surgery. This is a report of 76 patients with severe ARDS who were treated by ECCO2-R. Twenty-six of these 76 patients required thoracotomy: 19 for pneumothorax and pneumatocele, and seven for haemothorax, infected lung necrosis or oesophagotracheal fistula. Most pneumothoraces were bilateral. Ten of these 26 patients required reoperation, usually for extensive persisting alveolar air leaks. Sixteen (62 per cent) of the 26 patients who had a thoracotomy and 22 (44 per cent) of the 50 patients without surgery survived. These results demonstrate that performing a thoracotomy, if necessary, does not diminish the survival chance of high-risk patients with severe ARDS.

Adolescent↗
PubMed1990

Marburger concept for computer-aided acquisition, processing and documentation of patient data in the intensive care unit.

The authors report on their experience with the computer-aided acquisition, processing and documentation of patient data in an intensive care unit. The goal of an effective data and information collection system in the intensive care unit is to make therapy, and the patients respond to it, recognizable and understandable through the clear and complete representation of the patients conditions. The focal point of the data documentation is the medical record. In the implementation of a computer-aided data documentation and processing system the application of one central PC is unpractical. Each bed will be equipped with its own PC, and all the individual PCs will be connected to one central PC, which functions as server, and to connected to another PC in the doctors room. The data will be managed in a powerful database-management-system and be stored on an optical-disk. The development of an effective man/machine interface is especially important. In addition we can promote the user acceptance in other ways, so as to ensure a concrete benefit for each user group.

Electronic Data Processing↗
PubMed1990

[Extracorporeal membrane oxygenation and CO2 elimination].

The mortality in patients with ARDS stage IV is 90% according to the classification of Morel (1985) since all experiments as treatment with prostaglandine antagonists and application of antioxidants have to improve the outcome of such patients, we treated 87 patients, aged 5-51 years, between 1985-1990, with a veno-venous extra-corporeal bypass for CO2-elimination and with low frequency positive pressure ventilation according to the method of Kolobow et al. Forty-six of 87 patients survived, i.e. the mortality was reduced to 47%. This is striking evidence that this method is superior to other treatments of patients with ARDS.

Adolescent↗
PubMed1990

[The measurement of extravascular lung water--significant in the follow-up of ARDS?].

In 40 adult patients suffering from severe ARDS stage III and IV (Morel) we examined the course of the extravascular lung water (EVLW) measured by the double indicator dilution method with 858 single measurements, during mechanical ventilation with PEEP, or extracorporeal CO2 elimination (ECCO2 R). No correlation could be found between EVLW and the values of alveolar arterial oxygen difference (AaDO2) and intrapulmonary right-left shunt (Qs/Qt) or haemodynamic values such as CVP, PCWP, mean pulmonary arterial pressure, or the 24 h fluid balance. It was, therefore, not possible to estimate a prognostic trend based on a single measurement of EVLW. However, the course EVLW was more appropriate to perceive the prognostic trend of ARDS because a rapid decrease of very high EVLW was correlated with a decrease of AaDO2 (r = 0.87); whereas lethal ARDS (fibrosis) was associated with moderately increased, unchanged EVLW. However, during the ECCO2-R treatment the repeated estimation of EVLW and AaDO2 is a useful tool to assess recovery because other parameters such as Qs/Qt and chest computer tomography during long-term bypass are very difficult or impossible to employ for this purpose. A change of EVLW with increasing PEEP level could not be found. The reproducibility of 858 EVLW values was excellent with a coefficient of variation of 4.9 +/- 3.5%.

Adolescent↗
PubMed1990

[Surgical therapy of lung complications of long-term ventilation for severe adult respiratory distress syndrome].

Long-term respiratory therapy with high pressure levels in case of ARDS can lead to several symptoms requiring surgical treatment. Various forms of manifesting barotrauma predominate (bronchopleural fistula, pneumothorax, pneumatocele and soft tissue emphysema), while hematothorax, infected necrosis of parenchyma or esophagotracheal fistula are rare. Most of the operations became necessary because of bronchopleural fistula resp. pneumothorax, and with this indication the number of reoperations was especially high. Of 21 patients 13 (62%) survived.

Adolescent↗
PubMed1989

[Adult respiratory distress syndrome in legionella pneumonia--successful treatment with extracorporeal CO2 elimination procedures].

We report on successful treatment of an 46-year-old patient with ARDS (Adult Respiratory Distress Syndrome), caused by legionella-pneumophilia-pneumonia. The treatment with conventional artifical mechanical ventilation had failed. The new method of extracorporeal CO2-Elimination and low frequency positive pressure ventilation (ECCO2-R-LFPPV), introduced by L. Gattinoni (2) was in that case of severest ARDS very helpful. Supported by antimicrobial therapy with Erythromycin and Rifampicin the lung function could be improved to "restitutio ad integrum". Changes in chest radiographs, clinical parameters of ventilation, gas exchange and haemodynamics as well as the results of sequential pulmonary studies are demonstrated and discussed.

Carbon Dioxide↗
PubMed1989

[Personal experiences with extracorporeal CO2 elimination in patients with severe ARDS--a current review].

The method of extracorporeal CO2 elimination (ECCO2-R) as described by Luiciano Gattinoni and Theodor Kolobow is compared with earlier extra corporeal methods such as extracorporeal membrane oxygenation. The physiological fundamentals of the method, as well as indications and contraindications are explained. - The results of more than 100 patients treated worldwide are discussed together with the present problems of the method. In cases of severe ARDS stage IV, ECCO2-R definitely reduces mortality.

Carbon Dioxide↗
PubMed1989

[Dosage adjustment of drugs during continuous hemofiltration. Results and practical consequences of a prospective clinical study].

In 43 ICU patients undergoing continuous volume constant hemofiltration (CVHF), the pharmacokinetics of 12 drugs were investigated to ensure correct dosage adjustments. Under conditions of CVHF, maximum doses were defined for cefotaxime, ceftazidime, digoxin, digitoxin, imipenem, metronidazole++, netilmicin, phenobarbital, phenytoin, theophylline, tobramycin, and vancomycin. For the estimation of sufficient doses without blood level measurements, sieving coefficients (S) were calculated by a new method. In addition, S was integrated as a CVHF-specific factor into a common equation for drug dose adjustment in patients with renal insufficiency. The regression of dosage received from kinetics on blood-level-independent equation adjustment was r = 0.9923. Since the volumes of distribution in ICU patients are variable, it is suggested that further drug monitoring is necessary for toxic drugs.

Adult↗
PubMed1988

[Risk assessment and preliminary treatment in patients with esophageal cancer].

In 36 patients who underwent surgery for carcinoma of the oesophagus (21 patients subjected to blunt mediastinal dissection, 15 to thoracotomy) the preoperative status was determined by means of cardiopulmonary stepwise diagnosis and an individually adapted concomitant therapy was performed. A scheme for preoperative risk assessment which is equally important for both methods was evolved from the postoperative changes of VC, FEV1 and the preoperative values for RV/TLC, FEV1/VC, paO2 and paCO2 after retrospective analysis of the individual complication rates (60% cardiopulmonary). The 30-day lethality was 11%.

Adult↗