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Biomedical subjects

F W Ahnefeld

Publications and source records attributed to F W Ahnefeld.

At least 73 records · Page 4Linked to original sources
PubMed1989

[Frequency of colonization and pneumonia and development of resistance in long-term ventilated intensive-care patients subjected to selective decontamination of the digestive tract].

Colonization of the oropharynx with potentially pathogenic microorganisms (PPM) is a highly significant factor in the pathogenesis of bacterial pneumonia in intensive care patients. Via colonization of the oropharynx, bacteria pass into the tracheobronchial tree, where they can give rise to pneumonia after overcoming pulmonary resistance mechanisms. By a new, prophylactic antibiotic treatment schedule consisting in selective decontamination of the digestive tract (SDD) with locally applied nonabsorbable antibiotics, Stoutenbeek achieved drastic lowering of the colonization and infection rate in trauma patients. In the present study, we wanted to check whether this new prophylactic antibiotic schedule can be applied on a surgical intensive care ward in all patients with long-term ventilation, irrespective of the diagnosis, and whether it affords advantages over a conventional antibiotic schedule. MATERIALS AND METHODS. All patients on a surgical intensive care ward in whom it was expected that mechanical ventilation would be necessary for more than 4 days were included in the study. During the first 6 months 83 patients were investigated, in whom antibiotics were only administered when the presence of infection had been confirmed, in accordance with generally accepted guidelines (control group). In the second 6-month period, 82 patients were selectively decontaminated with 4 x 100 mg polymyxin E, 4 x 80 mg tobramycin and 4 x 500 mg amphotericin B, administered through the gastric tube and in an antimicrobial paste in the oropharynx (SDD group). The SDD schedule entailed systemic administration of cefotaxime in the first 3-4 days. RESULTS. In the control group, enterobacteria/Pseudomonas spp. were isolated significantly more frequently than in the SDD group (P less than 0.001): in the pharyngeal smear in up to 53%, in the tracheal secretion up to 36%, and in the rectal smear in up to 93% of the patients In the SDD group in the 1 week the frequency of gram-negative aerobic bacteria in the pharynx decreased from 33% to 5%, in the tracheal secretion from 23% to 14% and in the rectum from 86% to 52% (24% in the second week). However, the decrease in gram-negative microorganisms was accompanied by significant increase in the frequency of Staphylococcus epidermidis and enterococci. The SDD schedule proved to be effective with regard to the rate of infection. In the control group, 35 patients developed pneumonia (42%) as against 5 patients receiving SDD prophylaxis (6%). The duration of mechanical ventilation in the patients with pneumonia was 5 days longer than in patients without pneumonia.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1989

[An infusion of THAM (trishydroxymethylaminomethane) as therapy to lower increased intracranial pressure in acute craniocerebral injuries].

Despite of the use of all the current intensive care measures, some patients develop dangerously high intracranial pressures (ICP) after head injury. We have studied the use of THAM for the rapid control of dangerously high ICP in these patients. PATIENT AND METHODS. After all conventional methods of lowering ICP had been applied without sufficient effect, 1 mmol/kg body wt. THAM was given i.v. over a period of 10 min to ten patients with head injury. All patients were hyperventilated, sedated with thiopental (3-6 g/day), and the upper body was elevated to 30 degrees. The intracranial pressure and mean arterial pressure were monitored, arterial blood gas levels measured, and cerebral perfusion pressure (CPP) calculated. RESULTS. Our patients had a mean ICP of 37.4 Torr, which fell to 27.2 Torr within 10 min after the administration of THAM. The CPP rose from 46.5 to 56.3 Torr, no rebound was observed. There was no change in arterial blood gas values. DISCUSSION. Our study indicates that THAM not only decreases an elevated ICP, but also improves CPP. These results are of note because only patients with otherwise unresponsive increases in ICP were included.

Adult↗
PubMed1989

[The effect of adrenaline and noradrenaline on the oxygen supply of the myocardium during cardiopulmonary resuscitation].

The effect of epinephrine and norepinephrine on myocardial oxygen delivery and consumption during cardiopulmonary resuscitation using open cardiac massage after a 5-min period of electrically induced ventricular fibrillation was studied in 21 pigs with a mean body weight of 21 kg. Norepinephrine, like epinephrine, is a sympathomimetic agent with marked alpha- and beta-1-sympathomimetic activity, but the degree of beta-2-stimulation is less marked than that obtained with epinephrine. After mechanical measurements over 3 min (compression rate = 60/min), 7 animals received 10 ml physiological saline, 7 further animals, 45 micrograms/kg epinephrine, and the remaining 7 animals, 45 micrograms/kg norepinephrine. At 90 s and again at 5 min after the administration of epinephrine or norepinephrine, the mean arterial blood pressure was significantly higher than in the control group, while mean pulmonary artery pressure, central venous pressure and cardiac index were not significantly different. Total myocardial blood flow was only measured before the induction of cardiac arrest in the control group, where it was found be 193 +/- 30 ml/min/100 g. During the open cardiac massage but before the injection of catecholamines we found a myocardial blood flow of 51 +/- 23 in the control group, 71 +/- 10 in the epinephrine group, and 74 +/- 11 ml/min/100 g in the norepinephrine group. At 90 s after the injection, blood flow increased by 78% to 126 +/- 18, with epinephrine and by 45%, to 107 +/- 30 ml/min/100 g tissue with norepinephrine. At 5 min after administration of these catecholamines significant differences from the control group were present.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

The effect of epinephrine on hemodynamics, acid-base status and potassium during spontaneous circulation and cardiopulmonary resuscitation.

The effect of a bolus dose of epinephrine on hemodynamics, acid-base status and potassium during spontaneous circulation and cardiopulmonary resuscitation (CPR) was investigated in 24 pigs weighing 20-25 kg over a period of 10 min. In a study of 12 pigs in a stable hemodynamic condition, at the 1- and 2-min point after injection of epinephrine or saline the mean serum potassium concentration was significantly higher in the six animals given epinephrine (6.9 +/- 0.7 and 5.4 +/- 0.6 mmol/l, respectively) than in the six control animals (3.8 +/- 0.6 and 3.9 +/- 0.4 mmol/l, respectively). At the later points of observation (3, 4, 5 and 10 min after injection of either epinephrine or saline) no significant difference was found between the groups. Following 1 min of ventricular fibrillation 12 pigs were resuscitated by closed-chest CPR. Six of these animals received 45 micrograms/kg epinephrine (epinephrine group), the other six animals were given physiological saline (control group). Mean aortic diastolic pressure during the relaxation phase was significantly higher in the epinephrine group than in the control group. There was no difference in cardiac index or acid-base status between the groups. In the epinephrine group mean arterial serum potassium concentrations reached a peak value of 6.7 +/- 1.1 mmol/l at 3 min after injection, when they were significantly (P less than 0.05) higher than in the control group (4.4 +/- 0.5 mmol/l). At 5 and 10 min, the potassium levels sank to 5.9 +/- 0.9 and 5.6 +/- 0.8 mmol/l, respectively, in the epinephrine group, and were no longer significantly different from the control group.

Acid-Base Equilibrium↗
PubMed1988

[Not Available].

Explore the source record for details and available documents.

Anesthesiology↗
PubMed1988

[Arteriovenous pH- and carbon dioxide gradients during cardiopulmonary resuscitation].

During external cardiac massage and after restoration of spontaneous circulation, the arterial and central venous blood gas status of ten patients was determined. During cardiopulmonary resuscitation the median arterial pH value was 7.29 and the median central-venous pH value was 7.16. The low central-venous pH during resuscitation was probably caused by the high partial pressure of carbon dioxide, because no significant difference between arterial and central-venous base deficit was found. The arteriovenous pH and carbon dioxide gradients were significantly lower after spontaneous circulation had been restored. The arterial pH does not parallel the marked fall in central venous pH, and therefore only partly indicates acid-base changes during resuscitation. On the other hand, a central-venous blood gas status not only indicates the degree of metabolic acidosis present, but also the "respiratory" acidosis that in turn is a measure of the severity of intracellular acidosis.

Adult↗
PubMed1988

[Autologous blood transfusion. Goals and benefits, limitations and risks demonstrated in a practical concept].

Autologous transfusion as an alternative to homologous blood is useful, but its applicability is limited to a few patients, as we have shown in the autologous program at the University Hospital of Ulm. Each concept, even more an interdisciplinary one as autologous transfusion, includes risks. Risk factors arising primarily from donation and hemodilution are determined by the patient himself. As it is impossible to evaluate these risks in advance of anesthesia and surgical procedures the program has to provide guidelines and stringent limits to guarantee safety. Should these be ignored, the risks for the patient will be even higher than the risks of homologous transfusion that provide motivation for autotransfusion.

Blood Transfusion, Autologous↗
PubMed1987

Assessment of contractility changes in humans by transoesophageal echocardiography: the peak-systolic pressure end-systolic diameter relationship (PSPESDRS).

The peak-systolic pressure end-systolic diameter relationship (PSPESDRS) was determined in ten healthy subjects under general anaesthesia by using the radial artery pressure tracing (peak-systolic pressure) and transoesophageal 2d-and m-mode echocardiography (left ventricular diameters) without blocking of autonomic reflexes. Left ventricular load was changed by injection of a single intravenous dose of 0.2 mg nitroglycerin (NTG). Linear regression analysis showed a close linear relationship during the pressure decrease between peak-systolic pressures and end-systolic diameters. During infusion of dobutamine 5 micrograms/kg/min there was also a close linear relationship during pressure decrease with increased slope and unchanged Do (D0 = diameter at theoretical pressure zero). Values taken during pressure returning to control level were shifted leftward indicating transient increased contractility. We conclude, that the PSPESDRS can reliably be measured in humans without autonomic blockade during the decrease of arterial pressure after NTG, where reflex changes in inotropy are not yet present. This relationship increases in slope with dobutamine, reflecting the increased contractile state.

Blood Pressure↗
PubMed1987

Continuous positive airway pressure effect on functional residual capacity, vital capacity and its subdivisions.

Thirty-four otherwise healthy patients having to undergo elective upper abdominal surgery were randomly assigned to two equal groups. In the treatment group, constant positive airway pressure (CPAP) with an expiratory pressure of 12 cm H2O was applied at one hour following extubation, and at daily intervals for the first five days following surgery for a continuous period of three hours. The control group received no CPAP treatment. All patients were given postoperative physiotherapy. In patients who received postoperative CPAP with an end-expiratory pressure of 12 cm H2O, marked normalization of pulmonary function was noted.

Abdomen↗
PubMed1987

[Clinical studies of peripheral venous parenteral nutrition. Effect of a 3.5% amino acid solution on postoperative metabolism with special reference to amino acid homeostasis].

We studied 20 patients following vaginal hysterectomy until the third postoperative day. 10 patients (group I) in this randomized controlled study were infused only with water and electrolytes in a volume of 40 ml/kg BW. 10 patients (group II) received a 3.5% amino-acid solution with 6% carbohydrates in the same volume. In group II the nitrogen balance was significantly better than in group I. The nitrogen retention of 81% was judged as rather good. We have shown that there were no changes in the concentration of free plasma amino acids in group II, opposite we found significant changes especially in the branched-chain amino acids and alanine in group I. The normalization of metabolized amino acids and the normal concentration of the nonesterified fatty acids in group II demonstrated that the utilization of added amino acids took place not only in peripheral but also in visceral tissues. Our study indicates that the proven amino-acid solution can be recommended as peripheral-venous parenteral nutrition in the postoperative phase.

Amino Acids↗
PubMed1987

[Carbohydrate intolerance as a danger in infusion therapy].

The following types of carbohydrate intolerance are discussed as a risk in infusion therapy: Hereditary fructose intolerance, fructose-1,6-biphosphatase deficiency, impairment of glucose utilization during the post-aggression syndrome and/or in latent or overt diabetes mellitus. Asking about symptoms of fructose intolerance has to be part of every routine anamnesis. Application of any kind of carbohydrate requires differential therapeutic considerations. Undiscovered fructose intolerance is more likely the younger the patient is, whereas the frequency of glucose intolerance increases with age. In unconscious patients without anamnesis, fructose or sorbitol should not be applied. Never should an attempt be made to compensate falling blood glucose levels under infusion therapy by application of fructose or sorbitol. As carbohydrate addition to routine fluid and electrolyte substitution xylitol in the specified low dosage is without risk in a diabetes-like metabolic condition as well as in fructose intolerance.

Blood Glucose↗
PubMed1987

[Mechanical measures for cardiopulmonary resuscitation].

Recent investigations concerning different techniques in respiratory and circulatory assistance during CPR lead to the following conclusions: Ventilation should start with two slow insufflations. To minimize ventilation pressure, insufflation should be performed in a pause between compressions for 1-1 1/2 seconds in two rescuer CPR. Due to the high arterio-venous gradient in pH and pCO2 during CPR, arterial blood gas analysis is only useful for evaluation for ventilatory efficiency and oxygenation. Acid-base dysregulation can better be determined in mixed and central venous blood. Blood flow during resuscitation seems to be generated by direct ventricular compression and thoracic pump mechanisms. Which mechanism is dominant seems to be interindividually different. Therefore a compression time of 50% of the compression cycle should be maintained.

Animals↗
PubMed1987

[Behavior of blood gases in patients with craniocerebral trauma at the accident site and at the time of admission to the clinic].

It is known that early mortality after acute craniocerebral trauma (CCT) depends heavily on the extent of any hypoxia and, even more, hypercapnia in the early phase after the trauma. Hypoxia and hypercapnia are very difficult to appraise at the scene of an accident without measuring instruments. It is now generally recognized that appraisal in accordance with the Glasgow coma scale (GCS) is a suitable way of estimating the depth of impairment of consciousness (eye opening in response to stimuli, verbal response to stimuli, motor response to stimuli). The maximum number points is 15, and the minimum, 3. We therefore decided to investigate whether there is a correlation between the degree of impairment of consciousness measured with the GCS and onset of hypercapnia or hypoxia soon after. In 33 patients with acute CCT, arterial blood was taken for analysis of blood gases at the scene of the accident before therapy was started. At the same time, we evaluated the level of consciousness on the basis of the GCS. The blood samples were taken within 6-21 min after the trauma in all patients. It was shown that there is a very close correlation between the severity of trauma (measured with the GCS) and the degree of hypercapnia (r = -0.88). This was true of all CCT patients with multiple trauma without exception. The PaO2 correlates with the severity of trauma (r = 0.60) far less closely, and above all much less consistently.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Injuries↗