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Biomedical subjects

F W Ahnefeld

Publications and source records attributed to F W Ahnefeld.

At least 145 records · Page 8Linked to original sources
PubMed1980

[Bacterial contamination as a complication of intravenous therapy in intensive care (author's transl)].

Intravenous infusion therapy has become an indispensible part of intensive care. Problems of bacterial contamination during this therapy are well known. To check on the possible routes of contamination we examined the infusion system in its several parts (infusion solution, infusion system, connection between infusion system and catheter and content of syringes). The highest rate of contamination was found at the connection between the infusion system and the catheter after use for 24 h (26.7%, 39 out of 146 probes); just at the beginning of the infusion we found bacterial growth in 7.1% (10 out of 141 probes). After injection of drugs into the system the infusion solution was contaminated in 1.9% (6 of 320 probes). The system for measuring the central venous pressure was contaminated in 2.7% (4 of 148 probes). At the end of infusion the infusion solutions were contaminated in 3.1% (9 of 287 probes). Different drugs in syringes in no case were contaminated. In most cases (59 probes) we found gram-positive bacteria (87.3%), in only seven cases (9.7%) gram-negative bacterias and in two cases Candida tropicalis. Our results show that the extrinsic or in use contamination plays the most important part in bacterial contamination of the infusion system. Infection control of intravenous therapy necessitates care in the hygienic standard adopted during the infusion and injection procedures.

Antisepsis↗
PubMed1980

[Safeguarding the postoperative protein balance. Clinical studies on intravenous feeding].

In a randomized controlled study the influence of a low concentrated amino acid-carbohydrate solution (PE 900 with 25 g x 1(-1) amino acids and 50 g x 1(-1) Polyols) on the nitrogen support is investigated in the postoperative metabolism. The solution has a low osmolality of approximately 600 mosm x kg-1 and is, therefore, applicable during longer time via peripheral veins. Nitrogen retention was with 68% rather good. The effect of the regimen on protein and amino acid status is measured and discussed in detail.

Amino Acids↗
PubMed1980

[Peripheral venous amino acid substitution].

Under the aspect of the special function and importance of amino acids a modified procedure of infusion therapy via peripheral veins has been investigated. This regimen is characterized by the combination of amino acids with carbohydrates to ensure the minimal obligatory amount of glucose on which some tissues are dependent. On the basis of these investigations the concept of Blackburn et al. is discussed in detail where the main aspect concerns the question of endogenous energy supply by beta-oxidation of fatty acids. It is shown on the basis of gaz exchange measurements that under the treatment with the carbohydrate-containing solution the mobilization of NEFA non esterified fatty acids is not suppressed.

Amino Acids↗
PubMed1979

[Sorbitol and xylitol in post-operative infusion therapy (author's transl)].

The effect of a 24-hour continuous infusion of sorbitol in the recommended maximum dosage of 0.25 g . kg-1 . h-1 or of xylitol in the recommended maximum dosage of 0.125 g . kg-1 . h-1 on metabolic parameters was investigated in seven healthy adult men. The results demonstrate the continued applicability for longer than the recommended time as well as the acceptability of continuous infusion of polyols used clinically with combined solutions.

Adult↗
PubMed1979

[Effects of ventilation with defined formaldehyde concentrations on lung function and lung structures. Animal experiments on the noxiousness of formaldehyde residues after disinfection in the aseptor (author's transl)].

Having seen the development of fatal pneumonias in ventilated patients, the cause of which was assumed to be the presence of residual traces of formaldehyde in the air in the respirator Kilian and Haug showed in 1973 initial formaldehyde concentrations up to 0.2 ppm in the ventilatory air of respirators correctly disinfected in the Aseptor. To study the effects of formaldehyde on lung function and lung structures, 23 young pigs were automatically ventilated with defined formaldehyde concentrations during 6 hours. The concentrations used were 0.02 ppm, 0.2 ppm and 2.0 ppm (double of the maximum permissible concentration). We found no differences in lung function, as shown by compliance measurements and arterial blood gas analysis. No radiological differences were in the thorax. Histologically, there were only slight alterations in lung structure in the group ventilated with double the maximum permissible concentration of formaldehyde. We conclude that the disinfection of respirators using formaldehyde in the Aseptor will remain the method of choice.

Animals↗
PubMed1979

[Infusions emergencies following the administration of plasma substitutes -- analysis of case reports to the committee on drugs. The problems of medical statistics, prophylaxis and immediate therapy (author's transl)].

In the period 1967 to 1976 the Adverse Drug Reaction Committee of the Medical Association of the Federal Republic of Germany (AMK) received 323 reports of transfusion emergencies following the administration of colloid plasma expanders (dextran, gelatin, starch). The reports ranged from medium to severe cases. Nine percent of the reported cases had a fatal outcome. The data contained in these case reports could only be statistically analyzed within certain limitations as the reports were incomplete and other parameters necessary for a definite statistical evaluating were missing. Furthermore the results do not cover the following points: 1. What percentage of reactions to plasma expanders in W. Germany was reported? --2. What percentage can be attributed to the individual colloids within the entirety of these undesirable side effects? --3. What percentage of the individual colloids can be allocated to the varying degrees of severity of these reactions? -- Further limitations which complicated the analysis of the case reports are discussed individually. Despite these difficulties an attempt was made to analyse the parameters necessary in the diagnosis of acute transfusion emergencies and to compile a guide for the clinical symptomatology. Grading of reactions into four degrees of severity has proved useful both in terms of diagnosis and immediate therapy. The medical statistical evaluation presented in this paper gives an indication as to the significance of the observed side-effects and confirms the statement and recommendations made elsewhere in the literature. In these emergency cases life-threatening incidents appear to be more common than is generally assumed and the user is aware of. The incidence of product-specific emergencies can only be determined to some degree of accuracy by randomized prospective studies. These would have to be conducted with numerous strict guidelines. On the basis of the results presented here, these studies should be attended to with a sense of urgency. Regardless of the difficulties encountered in the evaluation of the case reports, guidelines as to the recognition of reactions, prophylaxis and immediate remedial therapy could be established. These would appear to suffice as urgently required comprehensive information for the nursing staff as well as all doctors. Recognizing side-effects and instituting immediate remedial therapy along the principles laid down in these guidelines can in most cases of severe reactions remove the acute threat to life.

Adolescent↗
PubMed1979

[A new suction pump to be used in the field of emergency medicine (author's transl)].

In the field of emergency medicine there has been a need for an efficient suction pump that can be used under all types of conditions and included both in doctors' emergency kits as well as in the standard equipment of mobile units such as ambulance cars, helicopters etc. The devices available in the past had decided disadvantages in their construction and performance. A newly designed suction pump -- the AMBU Uni-Suction -- has been subjected to laboratory and practical tests concerning function, material and practical use, based on a specification of requirements for such a device. The results show that this universally applicable suction pump meets every requirement under the different test conditions. The effectiveness is good, irrespective of the mode of operation applied, i.e. by hand, by foot or by compressed gases. Maintenance and service are negligible and no susceptibility to malfunction was observed. In addition, the design, function and performance of an accessory unit, the Suction Booster, are presented. This device can be used effectively in combination with the new suction pump, or with any other type of suction unit to prevent dangerous aspiration in emergencies.

Clinical Trials as Topic↗
PubMed1978

[Indications and possibilities for parenteral nutrition (author's transl)].

Parenteral nutrition is a basic therapy. It is necessary to have a preoperative definition of the nutritional condition and metabolism of the surgical patient. All disturbances such as catabolism and hypoproteinemia must be analyzed and treated. Patients in good general condition who need parenteral nutrition for more than two days receive a "basic nutrition" with 0.8-1.0 g amino acids and 4-5 mg carbohydrates/kg body weight/day, which may be given via peripheral veins. A "total parenteral nutrition" is always indicated if the patient is in a marked catabolic condition pre-operatively, or if it is anticipated from the extent of the operation procedure that parenteral replacement must continue beyond four days.

Amino Acids↗
PubMed1978

A new positive end-expiratory pressure valve for manually operated artificial ventilation.

The application of positive end-expiratory pressure (PEEP) as part of artificial ventilation is currently considered a basic provision to provide adequate treatment of critically ill patients in intensive care units. Hitherto only the application of intermittent positive pressure ventilation (IPPV) with an end-expiratory pressure of 0 cm water was possible during manually operated artificial ventilation. A new PEEP valve which can be attached to manually operated resuscitators has been developed in co-operation with industry to meet this need. The technical details and experimental testing of the new valve have been presented in this paper. It may be connected via special adaptors to existing Ambu resuscitators, either for use on adults or on neonates, babies and infants. The valve has the characteristics of normal PEEP devices in that the resistances with various PEEP levels remain relatively independent of the flow and thus presents a true positive end-expiratory pressure rather than just an increase of expiratory resistance. The valve can be connected simply to nearly all types of simple and advanced respirators, such as those used for assisting respiration, physiotherapy etc., as well as being used with manually operated resuscitators.

Adult↗
PubMed1978

[Clinical study on the concentration of free amino acids in plasma and urine during postaggression metabolism. I].

We studied the changes in the concentration pattern of free plasma amino acids in 30 surgical patients during standardized parenteral nutrition and exclusive water and electrolyte supply. Distinct reproducible differences were found in comparison to normal subjects. The concentration of branched-chain amino acids continuously increases during the post-operative period. The decrease of alanine is closely related. Phenylalanine also increases continuously due to insufficient transformation in the liver and increased release from the muscles. During post-aggression metabolism, cystine is probably not sufficiently formed from methionine and should be substituted. It may be that tyrosine is also essential for patients in the post-operative post-traumatic period. The glycine concentration of some amino acid mixtures is regarded as too high; the glycine content can be reduced in favour of serine supply.

Amino Acids, Essential↗
PubMed1978

[Clinical studies on the concentration of free amino acids in plasma and urine during post-aggression metabolism. II].

Our first report concerned the changes in the concentration of free plasma amino acids within the framework of postaggression metabolism, resulting from surgical intervention and parenteral nutrition. This study with 23 operated patients is intended to show whether an amino acid mixture is suited for parenteral nutrition if the particular metabolic action mentioned above is taken into consideration in the composition of the solution. We have shown that the change in the concentration of free plasma amino acids is very small during continuous infusion for 4 postoperative days in steady state and insignificant in comparison to the normal pattern of healthy subjects, except for phenylalanine. With a quota of 2.75% of the supply, the renal loss of free amino acids is clinically unimportant. We believe that an amino acid solution of such composition is suited for infusion in the postoperative and posttraumatic phase whereby our recommendation is explicitly limited to this indication.

Amino Acids↗