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Biomedical subjects

R Hettich

Publications and source records attributed to R Hettich.

At least 19 recordsLinked to original sources
PubMed1999

Long-term measurements of energy expenditure in severe burn injury.

The objective of this study was to evaluate resting energy expenditure (REE) in spontaneously breathing and artificially ventilated burn patients during the entire intensive care period. In 27 patients with 51 +/- 20% body surface area burned (BSAB) the REE was determined via indirect calorimetry. Three groups were formed according to the mortality prognosis index of Zawacki et al. In groups A, B, and C the predicted mortality rates were <20%, 20% to 80%, and >80%, respectively. The frequency of acute respiratory distress syndrome (ARDS), sepsis, renal failure, and mortality increased from group A toward group C. The REE test revealed wide individual variation and was usually overestimated by all tested formulas. The mean REE was comparable in groups A, B, and C during the first 20 days (49 +/- 16% vs. 59 +/- 21% vs. 57 +/- 18% above the REE calculated by the Harris-Benedict equation, or HBEE). The REE of patients in groups A and B declined after this period, whereas the long-term ventilated patients in the prognostically unfavorable group C showed a high REE up to the 45th day, usually accompanied by severe organ dysfunction and major metabolic disorders. During this time a nutritional regimen meeting the actual REE could not be achieved. In the clinical situation when indirect calorimetry is not available, REE can be stated to be 50% to 60% above HBEE in patients with >20% BSAB for at least 20 days. Expecting a stable clinical course in patients with a predicted mortality of <20% (group A), oral nutrition usually seems sufficient after a short period of artificial nutritional support (1 week). Patients with a predicted mortality of more than 20% have a complication-burdened clinical course and a prolonged period of ventilation (groups B and C). These patients need parenteral and enteral nutrition for at least 20 days after trauma to prevent severe malnutrition.

Adolescent↗
PubMed1995

Countinuous Laser-Doppler free-flap monitoring via the telephone line. Preliminary experiences.

It is possible to link a Laser-Doppler to a DOS-compatible personal computer in order to monitor microcirculation of the free flap after plastic surgery. We connected such a system to a second computer by telephone modems, in order to control the Laser-Doppler via the telephone line from a distant location using only commercially available hardware and software. The aim was to develop a low-cost system which would not require the purchase or construction of any specialised equipment. Using this system, it was possible to show the Laser-Doppler waveforms to colleagues who were not at the patient site, for their (more experienced) opinions without any further delays. Preliminary tests on five cases showed that it was indeed possible to transfer recorded information about the blood flow rate of free skin flaps from one computer to a remote one, without any loss of information. In these cases, the measured blood flow and clinical surveillance of the blood supply were adequate, thus making revision of the tissues not necessary. This preliminary study suggests that standard 'off-the-shelf' personal computer tools may be useful in improving the monitoring of microcirculation after plastic surgery.

Computer Peripherals↗
PubMed1995

Assessment of microcirculation of an axial skin flap using indocyanine green fluorescence angiography.

In many cases the complexities of skin-flap microcirculation are difficult to assess despite all the subjective and objective examination techniques available today. Adequate microcirculation is essential for tissue viability, so any method employed for studying microcirculation should provide as accurate an assessment of the prevailing conditions as possible. Of all the clinical methods, the fluorescence technique using the dye sodium fluorescein has so far provided the most reliable results. However, the pharmacokinetic properties of this tracer have prevented the technique from becoming established in clinical practice. The fluorescent dye indocyanine green (Cardio Green), on the other hand, has far more favorable pharmacokinetics. In an experimental animal model, the fluorescence technique using indocyanine green (indocyanine green angiography, ICGA) was used to study postoperative changes in the microcirculation of a skin flap. On the day of operation, indocyanine green angiography revealed a state of hemodynamic imbalance for which the organism was able to compensate in the postoperative phase with the aid of humoral, physical, and metabolic factors. With indocyanine green angiography it was possible to quantify objectively the new hemodynamic equilibrium. Basically, microcirculation may be quantified in temporal and spatial terms. The significant objectivity of indocyanine green angiography and short intervals between each examination favor its possible and meaningful use in clinical practice and give cause for continuing studies.

Angiography↗
PubMed1994

The immunogenicity of glycerol-preserved donor skin.

Previous clinical observations have suggested that the application of glycerol-preserved donor skin as a temporary wound dressing provokes a weaker rejection reaction than fresh, vital donor skin. Like others, we frequently observed that considerable parts of the allodermis not only remained on the wound for an extended period of time, but even became re-epithelialized in some cases. In order to quantify this effect, we applied the mixed lymphocyte culture (MLC) test in a rat model, using the two highly inbred, histoincompatible rat strains DA and Lewis as donor and recipient respectively. Using the methodology of the Euro Skin Bank, Beverwijk, The Netherlands, split thickness skin, excised from the back of the rats, was equilibrated in 98 per cent glycerol. The immunological reaction after grafting vital DA-skin, glycerolized DA-skin onto Lewis rats, and vital as well as glycerolized Lewis-skin onto Lewis rats was compared. The results of these experiments do not support the clinical observations that the glycerolization procedure results in decreased immunogenicity of donor skin.

Adult↗
PubMed1994

Treatment of skin defects using suspensions of in vitro cultured keratinocytes.

The in vitro cultivation of keratinocytes and their application in the form of confluent sheets to cover various kinds of skin defects involves a number of problematical steps which could be improved by using single cell suspensions instead. Therefore we developed a method to apply keratinocytes suspended as single cells in a fibrin gel. By testing the feasibility of this method in different experimental animal models we found that it facilitates cultivation as well as application of the cells, moreover, this method allows a much more flexible use of the cells, i.e. it is easier to consider the clinical condition of the patient than by the conventional method.

Animals↗
PubMed1994

[Ergospirometry in sarcoidosis patients].

Our investigation should clarify the question of whether cardiopulmonary exercise testing (CPX) offers additional information of clinical relevance in patients with pulmonary sarcoidosis. We investigated the relationship between changes of lung function including the diffusing capacity and the changes of gas exchange. Furthermore, we determined the correlation of functional and morphological lung changes on the basis of radiological parameters and on the influence of a steroid therapy over the gas exchange. Forty-seven patients with histologically diagnosed pulmonary sarcoidosis were examined. The lung function test includes the measurement of lung volumes with spirometry and the diffusing capacity of carbon monoxide in the single breath technique. Minute ventilation, oxygen uptake at maximum, oxygen pulse, functional dead space/tidal volume ratio, anaerobic threshold, and alveolar-arterial oxygen difference were measured continuously during exercise. We found significant correlations between the lung volumes and the CPX data. An increased relative minute ventilation and an increased alveolar-arterial oxygen difference with exercise allows a more objective differentiation in radiological stages I and II than does the lung function at rest. A steroid therapy improves the effectivity of alveolar ventilation and an improvement of the ventilation-perfusion-match. The CPX detects early changes of pathological gas-exchange, before the lung function at rest is evident pathologically. It offers additional information on the pathophysiology of sarcoidosis, and is useful in reviewing steroid therapy.

Adult↗
PubMed1993

[Herpes paronychia].

Herpetic whitlow is a rare viral infection, that should be treated nonoperatively and managed by a hand surgeon. There is a high risk of infection for dentists and other medical personal. The authors present a case, describe findings, possible complications, and treatment.

Animals↗
PubMed1992

Indication, technique, and results of plantaris medialis neurovascular island flaps.

Treatment of soft tissue defects in the heel often causes problems because of the anatomical structures of the foot and the foot's function in bearing the entire weight of the body. Various types of flap surgery have been tried, to deal with these problem areas. As ever, all the skin flaps lacked the normal quality of the plantar skin, which has fibrous septa with reduced flexibility. In view of the quality of the skin and subcutaneous tissue and the quality of the nerve supply, the technique of neurovascular island flaps for the plantaris medialis was used over the last 4 years in 14 patients, to conceal small to medium-sized heel defects. In this report, we examine anatomy, indication, technique, and results with regard to plantaris medialis island flaps. Their use is discussed in comparison with other types of flaps already used in this region.

Adolescent↗
PubMed1990

Increased survival rates by topical treatment of burns with cerium nitrate.

In experiments on mice we were able to show that the negative effects attributed to burn toxins could almost completely be prevented by one single early treatment of the burned skin with a 0.04 M solution of cerium nitrate [Ce(NO3)3]. The survival rate was 10% for animals which were grafted with burned skin. Treatment with Ce(NO3)3 increased the survival rate to 74%. A reflection of this protective effect was the prevention of the burn-induced disturbance of the acceptor control ratio in isolated liver cell mitochondria. Repeated use of Ce(NO3)3 showed adverse effects due to an increased absorption. An effective treatment of burns with Ce(NO3)3 is without problems and can be done in any hospital.

Absorption↗
PubMed1990

[Primary and secondary soft tissue injuries of the hand and therapeutic possibilities].

Primary treatment of soft tissue hand injuries is most important for further management and progress. It ensures best protection of lower structures. Soft tissue lesions that can not be closed without resulting tensions need instant plastic-surgical therapy. Various possibilities that range from split skin flaps to distant flaps with microvascular anastomosis can be chosen to cover primary as well as secondary soft tissue defects.

Hand Injuries↗
PubMed1990

[Pathogen spectrum and pathways of infection at an intensive care burn unit].

Coagulase-negative staphylococci have gained increasing importance in burns, whereas interest is no longer focussed on Pseudomonas bacteria. By means of microbiological analysis of swabs taken from patients, environment and staff, we trailed the routes of infection in an intensive-care unit for burns. Analysis of patients: In 27 out of 11 patients the same biotype of Staphylococcus epidermidis could be identified; 22 of these occurred in swabs from wounds. The phagotypification of Staphylococcus aureus showed the same phagotype in 28 out of 41 swabs taken from infected wounds of 10 patients. The pathogen mostly caused the destruction of already healed grafts in a later phase of the treatment. Further microbiological analysis showed a severe infestation of the patients by enterococci. Analysis of environment: Here, greatly increased counts of coagulase-negative staphylococci of the same lysotype as in the patients could be demonstrated. Analysis of staff: The naso-pharyngeal area is of minor importance in the spreading of germs, whereas that of protective clothing and especially the hands should be considered to be more crucial. Regular environmental tests enable rapid detection of hygienic errors so that appropriate countermeasures can be taken.

Adolescent↗