[New pediatric drug dosage aids. Improving patient safety]. / Neue Hilfsmittel zur Dosierung von Medikamenten im Kindesalter. Verbesserung der Patientensicherheit.

Dosing errors when administering medicine to children occur often and are due, e.g., to the commonly required dilution of the drugs, misjudgment of the patient's weight, confusion between drugs with similar names, and inadequate communication. Various aids (e.g., measuring tapes and dilution tables) have been designed to avoid mistakes to the greatest extent possible. In daily clinical practice, books and pocket cards are still used for rapid orientation. Use of smartphone-based apps continues to increase, whereby the user is ultimately responsible for their validity. In clinical practice, the simplest possible strategies should be used. A culture that encourages disclosure of errors is useful in order to optimize processes and avoid future errors.

Comparison of luteolytic potencies of aminoglutethimide enantiomers in the rabbit and rat.

The luteolytic potency of D- and L-aminoglutethimide (D- and L-AG) was compared in in vivo assays in the rat and rabbit. By assay of plasma progesterone depletion in the rabbit, the potency of L-AG relative to D-AG was 0.21. By the plasma procedure in the rat, the relative potencies of L-AG and of the racemic mixture to D-AG were 0.04 and 0.37, respectively. By the ovarian progesterone depletion method, the L-form had very little activity and the DL-mixture was half as active as the D-isomer. Thus, in both species, almost all of the activity of the racemic mixture results from the content of D-AG. Interpretation of paradoxical data implies that in the rat, L-AG may inhibit liver degradation of progesterone at levels which do not modify secretion from the corpus luteum.

[Functional importance of the m. extensor carpi ulnaris for distal radioulnar articulation]. / Funktionelle Bedeutung des M. extensor carpi ulnaris für das distale Radioulnargelenk.

Any analysis of the stability of the distal radio-ulnar joint should consider the extensor carpi ulnaris tendon. The static and kinematic function of this tendon depends on its relationship to the sigmoid notch of the radius. Morphological studies indicate the existence of a gliding surface in the sulcus of the tendon on the dorsal side of the ulnar head.

[Postoperative monitoring of microvascular flap repair with pulse oximetry--initial experience]. / Postoperative Uberwachung mikrovaskulärer Lappenplastiken mit der Pulsoximetrie--Erste Erfahrungen.

The surgical success of microvascular free flaps or pedicled flaps depends on the function of the nutritive vessels. Complications such as thrombosis or vessel kinking, are dangerous and may result in flap loss. During the last decade, different methods were tested for their capability of monitoring flap perfusion. We report our preliminary experience with the continuous and non-invasive pulse oximetry by using a special reflection sensor positioned on the surface of the flap.

[Suitability of capacitive sensors for measuring relative humidity in anesthetic gas systems]. / Eignung kapazitiver Sensoren für die Messung der relativen Feuchte in Narkosekreissystemen.

A capacitive sensor was tested for its suitability for measuring relative humidity in an anaesthetic gas circuit. The valvo sensor PH1 was tested using various different anaesthetic gas mixtures. Measuring accuracy was influenced neither by such volatile anaesthetics as isoflurane and halothane, nor by oxygen or nitrous oxide. The response time of the sensor depends on its position within the gas, and in the most favourable case is about 3 minutes. The sensor is readily incorporated within an existing gas circuit. The linearity of the characteristic curve must be corrected by external electronic compensation to avoid measuring problems in the lower humidity range.

[How relevant are calculations of mean intracompartmental pressure in functional compartment syndrome?]. / Wie relevant sind Mittelwertbestimmungen des intrakompartmentellen Druckes beim funktionellen Kompartment-Syndrom?

The intracompartmental pressure in the anterior tibial compartment was documented under standardized conditions in 29 patients walking at a speed of 4.5 km/h, as well as heel-and-toe running at a speed of 8 km/h. All pressure curves were integrated and the resulting mean pressure was compared with the arithmetic mean pressure indicated in the literature. During walking, the difference between calculated and integrated pressures was between 80 and 140%. In the case of heel-and-toe running, the difference was between 80 and 165%. On the basis of these results, the calculation of the mean intracompartmental pressure recommended in the literature does not appear to be of any clinical relevance.

[Arthroscopic treatment of anterior synovitis of the upper ankle joint in the athlete]. / Arthroskopische Behandlung der anterioren Synovialitis des oberen Sprunggelenkes beim Sportler.

UNLABELLED: In a retrospective study we analyzed the results of arthroscopic treatment of anterior synovitis of the ankle in 35 athletes. 5 athletes suffered additionally from anterior osteophytes and 3 presented with an anterolateral plica. Average age was 25 years (SD: 8.3) and follow-up interval was 32.4 months (SD: 19.4). 8 patients suffered from additional hyperlaxity of the ankle joint. At time of follow-up the patients were examined clinically as well as radiologically. The results were scored according to an ankle score containing the criteria pain, function, athletic activity, walking aids, range of motion, and swelling. During surgery a partial synovectomy was performed as well as removal of anterior osteophytes or anterolateral plica if necessary. The overall score increased non-significantly from 66.2 preoperatively to 78.7 postoperatively (p > 0.05). Comparing the different criteria the score parameter pain significantly increased after arthroscopy. All other parameters (function, athletic activity, walking aids, range of motion, swelling) showed only slight changes in this patient group. Athletes with hypermobile joint showed worse results compared to the others. Even after surgery we documented severe restriction in athletic activity. Only 9 patients performed their activities on their previous level, 19 reduced their activity level and 7 discontinued their athletic activity. In 6 cases we found iatrogenic temporary neurologic damage. CLINICAL RELEVANCE: Due to the uncertain clinical outcome and the documented high risk of neurovascular complications, patient selection for arthroscopic partial synovectomy in the athletic population should be performed extremely carefully. Prior to surgery, all other conservative options including changes of running shows as well as modifications in exercise program and athletic activity should be considered.

[Malignant hyperthermia in swine during isoflurane anesthesia]. / Maligne Hyperthermie beim Schwein in Isofluranenarkose.

A case of porcine malignant hyperthermia (MH) is reported, which occurred during a cardiological animal experiment under general anaesthesia using isoflurane as inhalational anaesthetic. Initially, tachycardia (238 bpm) and a sudden increase of end-exspiratory pCO2 were noticed. Discontinuation of isoflurane followed by administration of dantrolene (7 mg/kg body weight) led to a rapid recovery. Two days later, no difference in clinical state was apparent in comparison with the remaining swine. After regular euthanasia, acute muscle necrosis was seen macroscopically in back and glutaeal muscles, which was confirmed by histological examination. The rise of end-tidal pCO2 was the striking symptom thus allowing the detection of the incipient malignant hyperthermia. Early onset of dantrolene therapy is shown to be sufficient in termination of this hyperacute complication, and may prevent its deleterious outcome. Therefore, the administration of dantrolene should be taken into account in case of porcine MH, especially in time-consuming and costly series of animal experiments.

Accumulation of acetone in blood during long-term anaesthesia with closed systems.

During closed system anaesthesia with isoflurane, patients with a preoperative increase in blood concentration of acetone (> 10 mg litre-1) had a significantly greater concentration of acetone than patients with an initial normal blood concentration of acetone (P < 0.01). Flushing the closed system with a high flow of fresh gas had no effect on the blood concentration of acetone. Using a large fresh gas flow, there was no increase in blood acetone concentration. Acetone concentrations of about 50 mg litre-1 cause problems such as nausea and vomiting in the postoperative period. These symptoms occurred more frequently after closed system anaesthesia.

[Total intravenous anesthesia. On the way to standard practice in pediatrics]. / Total intravenöse Anästhesie. Auf dem Weg zum Standardverfahren bei Kindern.

Since venous cannulation in children has become easier and extensive experience has been gained with total intravenous anaesthesia (TIVA) in adults, the interest in TIVA for children has recently increased. An intensified sensitivity of the operating room atmosphere to contamination with volatile anaesthetic agents is another important reason to choose intravenous techniques for paediatric anaesthesia. One of the most interesting agents for TIVA in paediatric anaesthesia is propofol. The pharmacokinetic and pharmacodynamic data for modern intravenous drugs is poor. Because the interpatient variability is relatively large, pharmacokinetic data can only provide guidelines for the dosage of propofol. Propofol has a rapid and smooth onset of action and is as easy to titrate in children as in adults. Propofol can be excellently controlled. Severe haemodynamic side-effects are missing in healthy children and plasma is cleared rapidly of propofol by redistribution and metabolism. There is no evidence of significant accumulation, not even after prolonged infusion times. Because propofol has no analgetic properties it must be combined with analgetics or a regional block for all painful procedures. The combination with the ultra-short acting remifentanil is a major advantage, but requires effective analgetic concepts for painful procedures. In comparison the combination of propofol with long acting opioids abolishes some of the favourable properties of propofol. Further studies of the kinetics and dynamics of propofol and other intravenous agents are needed in paediatrics which should focus on age, maturity and severity of illness. The whole importance of the propofol-infusion syndrome has to be cleared up urgently. TIVA has an important significance in paediatric anaesthesia for diagnostic and therapeutic procedures, especially where these have to be repeated. In day-case anaesthesia TIVA has advantages for all short procedures and for ENT and ophthalmic surgery: even after prolonged infusion children have an short recovery time. There is no evidence of agitation or other behavioural disorders after TIVA with propofol in paediatric anaesthesia. Propofol has anti-emetic properties. TIVA with propofol can be combined with regional anaesthesia advantageously to provide long-lasting analgesia after surgery. TIVA with propofol has been used successfully for sedation of spontaneously breathing children for MRI and CT and other procedures with open airways like bronchoscopy or endoscopy. Propofol facilitates endotracheal intubation without the use of muscle relaxants. Of course, in malignant hyperthermia TIVA will continue to be the technique of choice. Nothing is known about awareness under TIVA in paediatric patients. TIVA must be considered by comparison with the volatile agents. The use of ultra-short acting agents may cause problems such as awareness, vagal response, involuntary movements and in some cases slow recovery after prolonged infusion of propofol. But it is not known exactly how often this happens during paediatric anaesthesia. With TIVA an effective postoperative analgesia must be provided. Newer administration techniques such as the target-controlled infusions or closed-loop control systems are under development and will help to minimise the potential risk of overdosage with TIVA in paediatrics. At the present TIVA is an interesting and practicable alternative to volatile anaesthesia for pre-school and school children. TIVA with propofol in infants younger than 1 year old requires extensive experience with TIVA in older children and with the handling of this special age group and should be undertaken with maximum precautionary measures.

[Arthroscopy of the upper ankle joint. List of indications from the literature--realistic expectations--complications]. / Arthroskopie des oberen Sprunggelenks. Indikationslisten der Literatur--realistische Erwartungen--Komplikationen.

Based on the results of a retrospective study of 116 patients who underwent diagnostic and surgical arthroscopy of the ankle, we present the technique, the results, the complications, and the indications for ankle arthroscopy. The average age of the patients was 33 years (range 10-70 years). At follow-up the patients were examined clinically as well as radiologically. The results were scored for the criteria pain, function, athletic activity, walking aids, range of motion, and swelling. The overall score increased significantly from 50.1 preoperatively to 73.7 postoperatively (P < 0.05). The decrease in pain and the improvements in function and athletic activity after arthroscopy were significant. The other parameters (walking aids, range of motion, swelling) showed only slight changes. The patients' subjective assessment (visual analogue scale) also revealed a significant increase, from 35.6 to 69.5 (P < 0.05). After arthroscopy the preexisting radiologic lesions continued to progress. Some 71.2% of the patients suffered no limitations their work at follow-up but 13.6% reported slight limitations and 15.3% experienced moderate limitations. We documented severe restrictions in athletic activity; only 17% of the patients had maintained their previous level. In 16 cases we found iatrogenic temporary neurologic damage.

Shoulder joint stability after arthroscopic subacromial decompression.

In 55 patients with type I or type II impingement lesions we performed arthroscopic subacromial decompression. Fifty-two patients are followed up 1 year postoperatively. In all patients the condition of the affected shoulder before and after decompression was documented using a 100-point shoulder score (pain on activity, 15 points; pain without activity, 15 points; function, 20 points; weight lifting, 10 points; muscle strength, 15 points; range of motion, 25 points). At follow-up we also documented the extent of passive inferior shift of the humeral head by ultrasound. The mean score preoperatively was 60.9 (+/- 13.8). Postoperatively there was a significant increase to 84.7 (+/- 12.5). The average postoperative hospital stay was 8.8 days (+/- 2.1). In 12 patients (23%) the postoperative score was less than 85 points, and in these the treatment was considered to have failed. Comparison of these patients as a group with those in whom the treatment was successful revealed no difference in age, a small but not significant difference in the preoperative duration of shoulder complaints, and no difference in the postoperative length of stay in hospital. However, there was a significant difference in the extent of passive inferior shift of the humeral head: in the failure group the mean inferior shift was 4.6 +/- 1.9 mm, while in the other patients the shift was only 2.7 +/- 1.0 mm. This difference was statistically highly significant. There was a statistical highly significant negative Pearson correlation coefficient of -5.56 between postoperative score and inferior shift of the humeral head. We conclude that patients with subacromial pathology and hypermobile glenohumeral joints may not be good candidates for subacromial decompression.

[The evolution of carboxyhemoglobin during long-term closed-circuit anesthesia]. / Die Entwicklung von Carboxyhämoglobin während Langzeitnarkosen im geschlossenen Kreissystem.

In 40 patients who underwent protracted orthodontic operations, the accumulation of carboxyhemoglobin (COHb) in the blood was studied. Mechanical ventilation during anesthesia was carried out in a closed system (group I, n = 20). Patients in a control group received mechanical ventilation with a constant fresh gas flow of 6 l/min (group II, n = 20). During closed-system ventilation, a constant rise of COHb was observed. Smokers had much higher COHb values than nonsmokers at the beginning of and during anesthesia. The relative increase of COHb in a defined time period was of the same magnitude for smokers and nonsmokers. Critical values for carbon monoxide (CO) intoxication were not measured. The mean rise was 0.05 g/100 ml COHb over 6 h. Two female patients had COHb rises of 0.29 g/100 ml and 0.18 g/100 ml over the same period. During ventilation with a high flow of fresh gas, the COHb level decreased in all patients. In nonsmokers, the value approached the physiological range of 0.4% to 0.8% COHb. A marked fall of COHb could also be observed in smokers; however, normal physiological values were not reached. Patients with low COHb tolerance (anemia, severe coronary heart disease, peripheral vascular disease) or with increased endogenous CO production (pregnancy, newborns, hemolytic disease, porphyria cutanea) should not undergo protracted ventilation in a closed circle system.

[Arthroscopic subacromial decompression. 1-3 year results]. / Die arthroskopische subacromiale Dekompression. 1-3 Jahresergebnisse.

In 148 patients with impingement lesion type I or type II, we performed an arthroscopic subacromial decompression (ASD). 122 patients ran a follow up one to three years post-operatively. All patients were pre- and postoperatively documented by a 100 point shoulder score. The mean score was 57.9 (+/- 11.5) preoperatively. Postoperatively there was a significant increase to 80.7 (+/- 17.9) (p < 0.05). 15% of the patients with a postoperative score less than 70 points were determined as failures. Patients with a preoperative pain history of more than one year had a significantly worse result (79.1 +/- 8.4) compared to those patients with a preoperative course less than one year (88.8 +/- 11.6) (p < 0.05). Other significant factors were the patient's age, and calcific tendinitis, whereas sex, preoperative range of motion, muscle atrophy, and degeneration of the acromioclavicular joint did not significantly influence the result. Our results after ASD in patients with subacromial pathology without a rupture of the rotator cuff are encouraging. Therefore, ASD seems to be a reasonable alternative to open acromioplasty.

[Humidification and heating of anesthetic gases during pediatric anesthesia using the Cicero Anesthesia Workstation]. / Klimatisierung anästhetischer Gase während Säuglingsnarkosen mit dem "Anästhesiearbeitsplatz CICERO".

A series of 52 infants underwent general or urological surgery; all were ventilated with the CICERO. Two different flows of fresh gas were used. In group I (n = 21) the fresh gas flow was set exactly at the level of the minute volume, representing a half-open, non-rebreathing system. In group II (n = 31) the fresh gas flow was adjusted to 10% of the required minute volume. Temperature and relative humidity of the inspired gas were measured continuously close to the tracheal tube. Anaesthesia was accomplished with 2 vol% isoflurane, 21-30 vol% oxygen in nitrous oxide. The results were compared with those achieved with our time-tested paediatric equipment, a SERVO 900D ventilator with a Fisher-Paykel humidifier (Group III, n = 35). Using a high fresh gas flow, no increase in relative humidity in the inspired gas could be detected. The values varied between 12% and 25% (group I). Reducing the flow of fresh gas as indicated above resulted in an increase in the relative humidity (group II). Over the evaluated period of 2 h, humidity increased slowly from an initial mean value of 20% to a maximum of something over 70%. Using the SERVO 900D ventilator combined with the Fisher-Paykel humidifier, humidity reached a value of greater 90% within 10 min after activation of the heated cascade. Humidity in the inspired gas should exceed 70% to avoid damage to infant airways. This will not be attained until after more than 2 h with unaided breathing systems, by when most operations performed on paediatric patients will already be over. Condensed water may aspirated by small infants. This potentially dangerous situation was only encountered in the CICERO circuit, and not in the system protected by the Fisher-Paykel cascade. Dry gases can result in thickened mucous and in obstruction of a small tracheal tube, which requires emergency reintubation. With artificial airways dry gases damage the ciliated epithelia of the trachea and cause loss of water and body heat. The temperature of the "cold" gases varied within a range of 21-33 degrees C and could not be adjusted by the anaesthetist. In the CICERO system, heating the gases at the valve only prevents mechanical failure caused by water condensation. In pediatric anaesthesia, variable heating and non-condensing humidity are essential. The dry and heated gases of the CICERO are not acceptable in the daily practice of paediatric anaesthesia.

[Intraoperative changes in arterial end tidal CO2 partial pressure difference in interventions with constant ventilation-perfusion ratio]. / Intraoperative Veränderungen der arterio-endtidalen CO2-Partialdruckdifferenz bei Eingriffen mit konstanten Ventilations-Perfusions-Verhältnissen.

During general anaesthesia, the endtidal CO2 pressure serves as an estimate of the arterial CO2 pressure to regulate the ventilator setting. Important arterial to end-tidal carbon dioxide tension differences (P(a-et)CO2) have been observed among patients undergoing procedures which have substantial impact on the ventilation-perfusion ratio (V/Q). Data on the P(a-et)CO2 for procedures in which the V/Q-ratio remains constant are lacking. Repeated measurements of P(a-et)CO2 in twelve patients with chronic obstructive lung disease (COLD) and nine pulmonary healthy patients undergoing jaw surgery were performed. The P(a-et)CO2 in the pulmonary healthy subjects (5.96 +/- 1.68 mmHg) was lower than in the COLD patients (9.05 +/- 3.49 mmHg) (p < 0.01). A clinically significant P(a-et)CO2 > or = 8 mmHg was observed in 52% of the measurements in patients with COLD compared with 11% in the pulmonary healthy subjects (p < 0.01). Both patient groups showed only minimal intraoperative changes of P(a-et)CO2. The deviation of all subsequent P(a-et)CO2 values from the initial P(a-et)CO2 was 2.17 +/- 1.52 mmHg in the pulmonary healthy patients and 2.02 +/- 1.49 mmHg in the patients with COLD (p = 0.76). Intraoperative changes of the P(a-et)CO2 are small during procedures with no major alterations of the V/Q ratio. For these procedures an initial measurement of the P(a-et)CO2 in patients with lung disease should be sufficient. In pulmonary healthy subjects the P(a-et)CO2 seems to be negligible.

Arthroscopic treatment of calcific tendinitis of the shoulder.

We evaluated 48 patients arthroscopically treated for calcific tendinitis. All patients' were treated by removal of the calcific deposit whenever possible and resection of the coracoacromial ligament. Those cases showing evidence of subacromial stenosis by x-ray evaluation or intraoperative findings were treated with an arthroscopic arcromioplasty during the same procedure. For postoperative functional assessment we used the Constant score. After surgery the Constant score significantly improved. All patients who were treated by acromioplasty showed significant flattening of the bony configuration of the acromion. The x-ray review showed that none of the blurred calcific deposits regained sharper borders after operation and also that no transparent deposit was converted into a denser appearance after the procedure. Those patients with postoperative elimination or reduction of the calcific deposits had significantly better outcomes than those who had no radiographic change. Acromioplasty did not improve the results. The aim of arthroscopic treatment in calcific tendinitis is to remove the calcific deposit.