Hoffa fracture: fixation using headless compression screws.

INTRODUCTION: Hoffa fractures are uni- or bicondylar fractures of the distal femur in a coronal tangential plane. CASE PRESENTATION: We report the case of an isolated, low energy, closed, displaced, lateral femoral condyle Hoffa fracture in a 54 year old Caucasian man. This was treated by open reduction and internal fixation using two headless compression screws. At 1 year review the patient was pain free, the fracture had radiographically united and there was a range of movement to his knee of 0°-100°. DISCUSSION: Traditional methods of fixation for Hoffa fractures have led either to the application of complicated constructs attempting to achieve stability, or to large articular surface defects created whilst countersinking headed lag screws. Both have negative implications for the patient. We describe a novel method, not previously described in the literature, using screws in a posterior to anterior direction. This provides compression perpendicular to the fracture site whilst protecting against shear and torsional forces, thereby providing more stable fixation. Furthermore, our method allows for a minimally invasive approach and uses headless compression screws, which reduces the chance of damage to the articular surface and is, therefore, less physiologically invasive.

[Axillary blockade of the brachial plexus. A prospective study of blockade success using electric nerve stimulation]. / Die axilläre Blockade des Plexus brachialis. Eine prospektive Untersuchung zum Blockadeerfolg mittels elektrischer Nervenstimulation.

Axillary block is a common anesthetic technique for operations on the hand and forearm. In our hospital, with many trainees in anaesthesia, only 250-300 axillary blocks per year are performed by about 30 colleagues. This implies a small number of blocks for each anaesthetist. The present study was designed to assess whether it is possible to teach this technique and use it with an adequate degree of success under these conditions. We used a nerve stimulator and studied whether the success of the block under these conditions is independent of anaesthetist's experience in this technique. Furthermore, we examined other factors involved in the success of the block. METHODS. The study included 112 patients subjected to elective surgery of the upper extremity; all received an axillary block. We used a nerve stimulator and injected mepivacaine 1% without adrenaline. The following parameters were recorded: the number of blocks to date performed by the anaesthetist; the minimal current required for nerve stimulation; the dose of local anaesthetic; the time between the end of injection and the beginning of surgery; the quality of sensory and motor blockade after 10, 20, and 30 min. Sensory blockade was assessed by the pinprick method (no blockade, analgesia, anaesthesia); motor blockade was judged by comparing the muscle strength of both arms (no blockade, paresis, paralysis). Data were analyzed using the Mann-Whitney test, with P < 0.05 considered statistically significant. RESULTS. Of the 112 blocks, 95 (85%) were successful; 17 (15%) failed and the patients required general anaesthesia. Eight of the successful blocks showed a decrease in analgesic quality after > or = 70 min and required additional analgesics or general anaesthesia. We found no correlation between the experience of the anaesthetist and the success of the block. The minimal required current for nerve stimulation in the success group was 0.4 mA and differed significantly from the value of 0.6 mA in the failure group (Table 3). The dose of mepivacaine was higher in the success group (5.9 vs. 5.3 mg/kg). Complete sensory blockade was more frequently achieved for the median, ulnar, and radial nerves than for the musculocutaneus and cutaneous brachii medialis (Fig. 3). The frequency of complete sensory blockade (anaesthesia) had increased by 21.9% between the 20th and 30th min. Complete motor blockade was less often achieved than sensory blockade (Fig. 4). CONCLUSIONS. Using the method of electrostimulation, the axillary block is an appropriate anaesthetic technique that can be applied in a hospital where each anaesthetist only occasionally performs it. Prior to injection of the local anaesthetic, the current for nerve stimulation should be reduced to < 0.5 mA. The time between the end of injection and the beginning of surgery should be no less than 30 min because complete sensory blockade can more often be achieved. The dose of mepivacaine should be no less than 6 mg/kg body weight.

[Combined intravenous administration of diclofenac and apazone for postoperative analgesia A randomized study of 112 patients with access to i. v. on-demand analgesia after minor orthopaedic operations.]. / Kombinierte intravenöse Gabe von Diclofenac und Azapropazon zur postoperativen Analgesie : Eine randomisierte Doppelblindstudie an 112 unfallchirurgischen Patienten mittels der intravenösen On-Demand-Analgesie.

In a double-blind, randomized, placebo-controlled study, 112 patients scheduled for knee-joint arthrotomies or minor orthopaedic operations received 75 mg diclofenac, 600 mg apazone, the combination of 75 mg diclofenac and 600 mg apazone, or placebo (50 ml NaCl 0.9%) as a single i.v. dose immediately after operation. Postoperative pain intensity was measured by a numeric rating scale. All patients were allowed to self-administer piritramide from a PCA (patient-controlled analgesia) pump (Prominjekt, Pharmacia, Sweden) in 2-mg boluses every 5 min during the first 6 h and subsequently every 15 minfor another 18 h after surgery. The patients receiving diclofenac, apazone, or the combination of diclofenac and apazone required a significantly lower cumulated dose of piritramide during the first 24 h after operation than did placebo-treated subjects (38 mg vs 39 mg vs 27 mg vs 67 mg;P<0.05), but there were no significant differences among the former three groups of patients. The incidence of typical side effects of opioids and antipyretic anti-inflammatory analgesics (nausea, vomiting, stomach ache, headache, vertigo) was low, and they were easily controlled in all cases. Postoperative combined application of the nonsteroidal anti-inflammatory analgesics diclofenac and apazone results in a significantly lower opioid requirement (about 60%) after minor orthopaedic surgery. The opioid-sparing effect appears to be superior to that of diclofenac (44%) or apazone (42%) alone, but this was not statistically significant.

[Perioperative endothelin, ACTH and cortisol plasma concentrations in coronary bypass patients]. / Perioperative Endothelin-, ACTH- und Kortisolplasma- konzentrationen bei Koronarbypasspatienten.

STUDY OBJECTIVE: To follow up endothelin (ET), adrenocorticotropic hormone (ACTH), and cortisol levels in patients undergoing aortocoronary bypass grafting (CABG) and to determine whether these are extracted from plasma by the pulmonary circulation. DESIGN: Convenience sample trial. SETTING: University hospital. PATIENTS: Eight male routine CABG patients without appreciable concomitant disease. INTERVENTIONS: Patients were given anaesthesia in a strictly standardised manner using etomidate, flunitrazepam, fentanyl, and pancuronium. Nitroglycerin was administered prior to cardiopulmonary bypass (CPB) at 2 mg/h and dopamine as the only catecholamine starting from CPB weaning until the end of sampling at 3.5-5 micrograms/kg.min. Samples were drawn in rapid sequence from cannulated radial and a distal pulmonary arteries (Swan-Ganz catheter) at eight sampling times starting after induction of anaesthesia and catheter placement and finishing 22 h after the end of operation. MEASUREMENTS AND RESULTS: ET levels were determined by an ET-1, 2, 3-sensitive radioimmunoassay (RIA), ACTH and cortisol by commercially available RIA kits. There was significant (P = 0.032, linear regression analysis) correlation between ET and cortisol from pulmonary arterial samples. ET was significantly (P = 0.042, two-tailed Wilcoxon test) extracted by the pulmonary circulation after induction of anaesthesia. This pulmonary-systemic arterial difference nearly disappeared intraoperatively, but tended to be restored 22 h after the end of operation at an approximately twofold increased level. CONCLUSIONS: No interrelation between ET and the hypothalamic-pituitary-adrenal axis could be established by the ET, ACTH, and cortisol plasma levels. However, the significant correlation between perioperative ET and cortisol lends further support to the hypothesis of ET release by cortisol from vascular smooth-muscle cells. There is a net pulmonary clearance of ET in patients prior to CABG that is lost intra- and early postoperatively, but tends to be restored on the 1st day thereafter at an increased level.

[Modification of ventilation and length of stay of traumatized intensive care patients by quality and duration of preclinical management]. / Beeinflussung der Beatmungs- und Liegedauer traumatisierter Intensivpatienten durch Qualität und Dauer der präklinischen Versorgung.

AIM: The study aimed at detecting relations between the quality and duration of prehospital care in the case of traumatic patients and the duration of artificial respiration and ICU stay times. DESIGN: 94 traumatic patients, admitted to the intensive care unit, were subdivided into groups according to the type of trauma. The mean time of prehospital care, injury severity score, the Apache II at the admission to the clinic and the discharge to the ICU, intraoperative replacement of blood and clinical care times were calculated. RESULT: In the group of all patients, times of the ICU-stay were correlated to the ISS and the Apache II of the hospital admission. In the group with multiple fractures, a positive correlation to the prehospital care times was found. DISCUSSION: Quality and duration of the prehospital care were identified as factors, influencing the time of the ICU stay. Optimizing these factors will be helpful in respect of economic considerations.

Sternal closure with resorbable synthetic suture material in children.

The use of resorbable sutures for sternal closure after median sternotomy in children has developed to a clinically routine procedure. Since there is no follow-up study so far about the influence of these synthetic sutures on sternal stability, wound healing, and compatibility in children, we evaluated the use of polydioxanon (PDS) cord in children particularly regarding those properties. In 59 children (weighing up to 30 kg) we could show that the use of synthetic resorbable materials (Vicryl 4/0, PDS) allows a complication-free stability of the sternum, good wound healing, and very good compatibility. It is concluded that the use of PDS cord is a suitable and reliable method for sternal closure with good clinical results.

Performance characteristics of a novel reusable intermediate-volume low-pressure cuffed endotracheal tube.

STUDY OBJECTIVE: To evaluate the performance of the reusable intermediate-volume low-pressure cuffed "Super Safety Yellow" (Willy Rüsch AG, P.O. Box 1620, D-71332 Waiblingen, Germany) endotracheal tube with regard to cuff seal, tube tip position, and incidence of postoperative throat complaints. The "Super Safety Yellow" was compared with the "Super Safety Clear" (W. Rüsch AG), the "lo-pro (Mallinckrodt Laboratories, Cornamady, Athlone County, Ireland), and the "red rubber" (W. Rüsch AG) tubes. METHODS: Two hundred adult patients scheduled for minor surgery under standardized general anaesthesia were allocated to one of these tubes. Past-cuff leakage (indicator; orally instilled 0.2% indigocarmine) as well as intratracheal tube tip position (degree of being centred) were assessed by fibre-optic tracheoscopy. The semi-standardized interviews for the recording of postoperative sore throat were performed in double-blind fashion once a day, starting on the day of operation till p.o. day 3. STATISTICS: chi 2-test; significance: P < 0.05. MAIN RESULTS: A past-cuff leakage was found in three "red rubber" tubes. There were significant differences in tube tip position with the "Super Safety Clear" being best, and the "Super Safety Yellow" being worst centred (P = 0.010). The incidence of postoperative throat complaints showed a nonsignificant tendency in favour of the PVC-tubes. A significant number of such complaints were observed in women (P = 0.0004) and in obese patients (P = 0.011). By contrast, this incidence did not significantly differ with age, tracheal cross-sectional shape, tube tip position, use of atropine, and duration of intubation. CONCLUSION: Although resembling the "red rubber" tube in the incidence of postoperative throat complaints, the "Super Safety Yellow" may be an alternative to the currently used disposable tubes in anaesthesia. Its performance is comparable with regard to cuff seal and intra-cuff pressure. Additionally, it helps in reducing PVC waste and may lessen costs.

[The effect of theophylline on the mucociliary clearance function in ventilated intensive care patients]. / Einfluss von Theophyllin auf die mukoziliäre Klärfunktion beatmeter Intensivpatienten.

Mucociliary clearance represents an important protective mechanism of the upper and lower respiratory tracts whereby inhaled particles and micro-organisms are removed from the tracheobronchial system. In incubated intensive care unit (ICU) patients, impaired ciliary function and mucus transport are associated with pulmonary complications [9]. Some authors have shown that theophylline increases mucus transport in healthy subjects and patients with chronic bronchitis [8, 16, 31, 36]. However, other investigators have found unconvincing or conflicting results [4, 20, 25]. Therefore, we studied the influence of theophylline on bronchial mucus transport velocity (BTV) in ventilated ICU patients. METHODS. The study was approved by the ethnics committee of our hospital. In a placebo-controlled double-blind study, the effect of therapeutic serum concentrations (10-20 micrograms/ml) of theophylline on BTV in ventilated patients in a surgical ICU was investigated. Group 1 (n = 10) served as controls and received placebo. The patients of group 2 (n = 10) were given intravenous infusions of 5 mg/kg body weight theophylline over 20 min, followed by 1 mg/kg per hour. Before administration of theophylline and 1 h after starting the infusion BTV, serum theophylline concentrations, and arterial blood gases were measured. Heart rate and blood pressure were registered every 5 min. In an additional study, the effect of theophylline on BTV at subtherapeutic serum concentrations (5 micrograms/ml) was investigated. BTV was measured with a small volume (0.05-0.08 ml) of albumin microspheres labeled with technetium-99m, which was deposited on the dorsal surface at the lower ends of the right and left main bronchi via a catheter placed in the inner channel of a fibre-optic bronchoscope. The movement of the microspheres towards the trachea was visualised and recorded using a scintillation camera [10]. RESULTS. The theophylline treatment induced a significant improvement in BTV from 3.8 to 7.6 mm/min in the left main bronchus and from 0.5 to 5.4 mm/min in the right, while placebo was inactive. The increase in BTV, however, was associated with an increase in heart rate; in 3 patients the theophylline infusion had to be stopped because of severe tachycardia. Blood gases and blood pressures did not change. Theophylline at subtherapeutic concentrations had no effect on either BTV or heart rate. CONCLUSIONS. Theophylline at therapeutic concentrations improves bronchial mucus transport in intubated ICU patients. The increase in BTV may be associated with severe tachycardia, and therefore routine application cannot be recommended.

Pharmacokinetics and technique of endotracheal and deep endobronchial lidocaine administration.

To determine absorption characteristics of endotracheal lidocaine, we administered lidocaine to hemodynamically stable patients by different techniques. Blood samples were taken for measurement of lidocaine plasma concentrations (fluorescence polarization immunoassay), and pharmacokinetics were calculated by regression analysis. Plasma concentrations at 1.5 and 2 min after drug administration were higher (P < 0.05) after instillation into the endotracheal tube (1.40 +/- 0.19 and 1.26 +/- 0.14 microgram/mL) than after deep endobronchial administration (1.00 +/- 0.08 and 0.83 +/- 0.05 microgram/mL). A biphasic absorption with a division of the area under the curve (AUCtot) into two parts (AUC1 and AUC2) could be assumed. After tube instillation, the AUC1/AUCtot ratio (2.6%) was higher (P < 0.05) than after deep endobronchial instillation (1.1%). To achieve high plasma concentrations within a short time, AUC1, representing a nearly instantaneous absorption, seems to be more important than AUC2, representing a higher but delayed absorption (depot effect). Because deep endobronchial lidocaine administration accentuated the late absorption, presumably by preventing drug distribution to the whole lung, this technique was detrimental to obtaining high plasma concentrations within a short period of time.

[A comparison of different endotracheal tubes. Tracheal cuff seal, peak centering and the incidence of postoperative sore throat]. / Vergleich verschiedener Endotrachealtuben. Trachealabdichtung, Spitzenzentrierung und Inzidenz postoperativer Halsbeschwerden.

UNLABELLED: The study objective was to evaluate cuff seal, tube tip position and incidence of postoperative sore throat in three different endotracheal tubes: the reusable Rüsch "red rubber" tube (low-volume, high-pressure cuff) and the disposable Rüsch "Super Safety Clear" and Mallinckrodt "lo-pro" tubes (both high-volume, low-pressure cuffs). METHODS: In a prospective randomized trial, 150 consecutive patients scheduled for minor orthopaedic surgery under standardized general anaesthesia, including standardized cuff pressure control, were allocated to one of the three types of endotracheal tube. Leakage and intratracheal tube tip position were investigated by means of fiberoptic tracheoscopy via the endotracheal tube, preceded by pharyngeal instillation of indigocarmine. The semi-standardized interviews for the recording of postoperative sore throat were performed once a day under double-blind conditions from the day of operation to postoperative day 3. Statistical independence testing was based on the chi 2-test, significance was assumed at P < 0.05. MAIN RESULTS: A past-cuff leakage of the pharyngeally instilled dye was found in three patients with "red rubber" tubes. In all of these cases the tracheal cross section deviated markedly from circular. The tips of the "Super Safety Clear" tubes tended to be better centred (P = 0.099). Bad tip position, however, had little influence on postoperative throat complaints (P = 0.394). The differences in incidence of postoperative throat complaints between the "red rubber" (48.9%), "Super Safety Clear" (35.6%) and "lo-pro" tubes (34.1%) did not reach the 5% level (P = 0.288). Such complaints, however, were significantly more frequent in females and in obese patients who exceeded their Broca weights by more than 25%. By contrast, postoperative throat complaints did not vary statistically significantly by age group, tracheal cross-sectional shape, use of atropine or duration of intubation. CONCLUSION: Despite the economic (usable up to 100 times) and ecological (less PVC waste) advantages of the rubber tube, the disposable tubes with high-volume, low-pressure cuffs tended to be superior regarding cuff seal, tube tip position and incidence of postoperative throat complaints. Nevertheless, the continued use of "red rubber" type reusable tubes may be justified in cases where the tube has to stay in place for only a short time.

[Bronchoscopy for initial care following severe thoracic trauma--basically indicated?]. / Bronchoskopie zur Erstversorgung nach schwerem Thoraxtrauma--grundsätzlich indiziert?

UNLABELLED: The study objective was to determine the usefulness of routine early (within 24 h after admission) and late (on the 3rd posttraumatic day) flexible fiberoptic bronchoscopy in patients with severe chest trauma. METHODS: By history, physical examination, and radiologic findings, we identified 15 consecutive patients, all of whom were anaesthetized, orally intubated, and mechanically ventilated. There was no change in ventilation, including FIO2, for bronchoscopy. The patients had continuous cardiovascular monitoring and peripheral pulse oximetry. The bronchoscope was inserted through a tight-fitting side port at the endotracheal tube connector. Pulse rate, mean arterial pressure, and arterial blood gases were recorded before, 1 min after, and 10 min after bronchoscopy, as were intracranial pressure (ICP) in 7 patients with an ICP probe (early bronchoscopy only) and the duration of the examination. Statistical significance was tested by means of the Wilcoxon test for correlating samples. Significance was assumed at P less than 0.05 in a two-sided test. RESULTS: Early bronchoscopy revealed two bronchial avulsions, two aspirations, and ruled out one suspected aspiration. Late bronchoscopy showed plugging of at least 3 segmental bronchi by clots in 4 patients, none of whom was able to expectorate effectively. In general, changes in the observed vital parameters were minimal. There was a significant but clinically irrelevant increase in mean pulse rate before and 1 min after early bronchoscopy. DISCUSSION: We conclude that bronchoscopy should always be considered in patients with severe chest trauma, the decision being based on typical radiological findings as well as clinical signs and symptoms. Given the proper indication, bronchoscopy supplies valuable information at minimal risk to the patient.

[Experimental studies on the recovery of anesthetic gases]. / Experimentelle Untersuchungen zur Rückgewinnung von Narkosegasen.

The volatile anesthetic agents halothane, enflurane, and isoflurane are chlorofluorocarbons (CFC) and contribute to ozone depletion. Although the contribution is small, its importance is rising, as technical CFCs will be phased out according to the Montreal protocol (1987) and the London conference (1990) by the year 2000. Alternative procedures and CFC-free volatile agents such as des- and sevoflurane do not contribute to depletion of the ozone layer, but will not replace standard methods using volatile anesthetic agents in the near future. METHODS. In an experimental setup, we filtered anesthetic waste gases from scavenging systems of rebreathing circles by activated carbon filters. The filtered substances were desorbed by a heat chamber and condensed in a cold trap. RESULTS. By this method, it was possible to retrieve 50%-60% of the applied gases. Gas chromatographic analysis showed halothane containing traces of pollutants and isoflurane and enflurane as pure substances. DISCUSSION. The retrieval of anesthetic waste gases is easy; no sophisticated technical equipment is necessary. Purity of substances could make recycling possible and offer a method to avoid environmental pollution by volatile anesthetics.

Can a clinician predict the technical equipment a patient will need during intensive care unit treatment? An approach to standardize and redesign the intensive care unit workstation.

The technical equipment of today's intensive care unit (ICU) workstation has been characterized by a gradual, incremental accumulation of individual devices, whose presence is dictated by patient needs. These devices usually present differently designed controls, operate under different alarm philosophies, and cannot communicate with each other. By contrast, ICU workstations could be equipped permanently and in a standardized manner with electronically linked modules if the attending physicians could reliably predict, at the time of admission, the patient's equipment needs. Over a period of 3 1/2 months, the doctors working in our 20-bed surgical ICU made 1,000 predictions concerning outcome, equipment need, duration of artificial ventilation, and duration of hospitalization for 300 recently admitted patients. The interviews were made within the first 24 hours after admission. The doctors being interviewed were usually (i.e., in over 90% of cases) unfamiliar with the patient. Information concerning the patient's general state of health, special pre-ICU events, and complications was offered to the interviewed clinician because this information represents standard admission data. It was found that the equipment need (represented by two different setups, "high tech" and "low tech") could be predicted most reliably (96.4% correct predictions) compared with a prediction on outcome of ICU treatment (94.5%), on duration of artificial ventilation (75.4%), and on duration of stay (43.4%). There was no significant (p greater than 0.05) difference in the reliability of predictions between residents and consultants. Factors influencing the postoperative equipment need varied with surgical specialty.(ABSTRACT TRUNCATED AT 250 WORDS)

[The "preoxygenation" special function in mechanical ventilators. Medically necessary and an ergonomic plus?]. / Sonderfunktion "Präoxygenierung" am Beatmungsgerät. Medizinisch notwendig und ein Plus an Ergonomie?

Hypoxia-related cardiovascular complications and unnecessary monitor and ventilator alarms are well-known problems during tracheobronchial suctioning. Preoxygenation together with temporary muting of acoustic alarms for tracheobronchial suctioning are provided by a single operational control of the ventilator "Evita", software release 9 (Drägerwerk AG). This integrated function was evaluated in medical and ergonomic respects. METHODS. Thirty tracheobronchial suctioning procedures each, with or without preoxygenation, were evaluated. The subjects were patients in our anesthesiological intensive care unit who were under continuous positive-pressure ventilation with FIO2 between 0.25 and 0.6. They ranged in age from 18 months to 72 years. Each patient served as her/his own control after about 1-h delays. Depending on the preference of the nurse, the procedures were either both on-ventilator (via the catheter port) or both off-ventilator suctionings. Arterial samples for blood gas analyses as well as arterial oxygen saturation (SaO2) determinations were taken before preoxygenation, at the moment of disconnection or opening of the catheter port, at reconnection or closure of the port, and 5 min later. Moreover, the number of changes in position of the performing nurse, the number of acoustic ventilator alarms, and the duration of the procedure were recorded. Finally, assessments of the integrated ventilator feature by the 28 participating nurses were collected both as a score from 1 ("most useful and innovative") to 5 ("completely superfluous and distracting") and as detailed statements. RESULTS. Arterial blood gas results and SaO2 courses differentiated as to procedures with or without preoxygenation as well as on-ventilator and off-ventilator suctioning are shown in Table 1 (values are mean +/- standard deviation). Without preoxygenation, most patients did not exhibit threatening drops in SaO2 (values fell from 98.2%) to 97.0% on the average). Nevertheless, preoxygenation provided an additional safety margin (100% saturation throughout the procedure in all patients). Under certain conditions, e.g., low functional residual capacity as in small children or patients with adult respiratory distress syndrome (in 1 of these cases we observed a SaO2 drop to 87%), it is mandatory. Although occurring far less frequently, unnecessary acoustic alarms were not completely excluded by the integrated function because the ventilator would not recognize the insertion of the suction catheter via the catheter port as the expected disconnection. Thus, coughing was able to trigger the "high airway pressure" alarm. As expressed by an average score of 2.8, approval of the integrated ventilator function prevailed among the involved nursing staff.

Endotracheal and endobronchial lidocaine administration: effects on plasma lidocaine concentration and blood gases.

OBJECTIVE: To compare four different methods of endotracheal lidocaine administration with respect to the site of administration. DESIGN: Randomized controlled trial. SETTING: University hospital. PATIENTS: Thirty-two female patients (43.6 +/- 11.5 years old) undergoing elective gynecologic operations with an anesthesiologic risk classification not higher than ASA II. All patients gave their written informed consent to participate in the study. INTERVENTIONS: Lidocaine at a dose of 2 mg/kg, diluted with normal saline to a total volume of 10 mL, was administered to eight patients by instilling the drug solution from a 10-mL syringe directly into the outer aperture of the endotracheal tube. All other study patients received lidocaine under bronchoscopic control through the work channel of the bronchoscope either a) deep endotracheally, b) into the right main bronchus, or c) into the right lower lobe bronchus. At 10 points in time after drug administration, blood samples were taken for measurement of lidocaine plasma concentration (using high-pressure liquid chromatography) and blood gas analysis. MAIN MEASUREMENTS AND RESULTS: Therapeutic blood concentrations (greater than or equal to 1.4 micrograms/mL) could be achieved and toxic blood concentrations (greater than or equal to 6 micrograms/mL) could be avoided with all methods of administration. No significant difference was found between the different methods with regard to peak concentration, time to peak, onset and duration of therapeutic levels, or relative bioavailability. A significant (p less than .05) decrease in PaO2 to 75% of the baseline was seen with all methods used. CONCLUSIONS: Because no route of lidocaine administration was superior to the others, the simplest method (instillation into the endotracheal tube) should be used.

Endobronchial drug administration: does deep endobronchial delivery have advantages in comparison with simple injection through the endotracheal tube?

Endobronchial administration of drugs is a valuable alternative to intravenous delivery when venous access cannot be established quickly enough. Some authors propose that deep endobronchial administration through a catheter or similar auxiliary device should give better absorption than simple injection through the endotracheal tube. To test this proposal in the present study two groups of each 6 patients during general anesthesia were administered 3 ml aqueous lidocaine solution at a dose of 2 mg/kg, either deep endobronchially through a catheter or simply through the endotracheal tube. The unusually low volume of administration of 3 ml was chosen because it was thought that the advantages of deep endobronchial administration would then be particularly apparent as 3 ml would lead to a more localized deposit with deep endobronchial administration thus being clearly different from simple injection. No difference in the PaO2 between the two groups could be statistically established. However, the mean lidocaine plasma concentration in the group with the deep endobronchially administered drug was in tendency lower than in the control group (P less than 0.05 at 5 min after delivery). Presumably because of the low volume of administration the mean lidocaine plasma concentrations in both groups always remained under the therapeutic level of at least 1.5 micrograms/ml. Thus, at least for small volumes and stable circulation the results after deep endobronchial administration through a catheter were somewhat worse than after simple injection through the endotracheal tube.

Plasma lidocaine levels and PaO2 with endobronchial administration: dilution with normal saline or distilled water?

STUDY OBJECTIVE: To determine whether water or 0.9% saline should be used as diluent for endobronchial drug administration. PARTICIPANTS: Twelve adult patients. INTERVENTIONS: Patients were endobronchially administered 2 mg/kg lidocaine as marker substance in either 10 mL 0.9% saline or 10 mL distilled water during general anesthesia. MEASUREMENTS AND MAIN RESULTS: The differences in mean lidocaine plasma levels at five minutes (water vs saline, 2.35 vs 1.59 micrograms/mL) and ten minutes (water vs saline: 2.67 vs 1.88 micrograms/mL) were significant (P less than .05). With the initial mean PaO2 being almost (157 mm Hg; F1O2, 0.3) in the two groups, there was a mean drop of about 60 mm Hg in the saline-diluent group, but only about 40 mm Hg in the water-diluent group one minute after administration (P less than .05). CONCLUSION: The use of water resulted in better absorption of lidocaine and less impairment of the PaO2.

What is the optimal volume of administration for endobronchial drugs?

During general anesthesia, three groups of six patients each received 2 mg/kg lidocaine as a marker substance endobronchially in either 10, 5, or 3 mL distilled water. It was found that the group receiving 10 mL initially exhibited the highest lidocaine plasma concentration with a mean of 2.01 micrograms/mL, in comparison with 1.25 micrograms/mL in the 5 mL group and 0.95 micrograms/mL in the 3 mL group. After about 10 minutes, concentration courses were almost the same in the 10 mL and the 5 mL groups. The PaO2 in the 10 mL group dropped initially by approximately 40 mm Hg on average and remained low over 60 minutes. By this time the PaO2 in the 5 mL group (initial drop 46 mm Hg) had come back to the original value (P less than .05). The 3 mL group exhibited even more favorable courses in the PaO2 (initial drop 16 mm Hg on average). However, the lidocaine plasma concentration was at the lowest at all times in this group and, moreover, under the therapeutic level of 1.5 micrograms/mL with the dosage used.

[Analysis of data management in anesthesia from an ergonomic viewpoint]. / Analyse des Datenmanagement in der Anästhesie aus ergonomischer Sicht.

In the perioperative phase the anesthetist has to manage an increasing amount of knowledge, information and data. Using a system-ergonomic approach we can define three types of data management (DM): Exploratory DM, Operative DM, Concluding DM. The preliminary examination of the patient is Exploratory DM. Data are collected and recorded. Here, a well structured form prevents things being forgotten, provides forgetting anything. Help from electronic devices is not available. Control of anaesthesia is based on Operative DM. The anesthetist is part of an ongoing process. He investigates and records a situation based on his knowledge and experience and a prompt reaction to untoward circumstances may be necessary. Today's workplace provides insufficient support for this task. Data presentation is unstructured and distributed around the workplace which produces potentially dangerous overloading in critical situations. It is necessary to view the work layout as an integrated whole. The data being displayed must be hierarchically structured and appropriate to the situation. Concluding DM involves summarising data and information on completion of a process in ways appropriate to specific purposes. With this the anesthetist completes an anaesthesia and transfers the patient to the next unit, e.g. to the recovery room. He has to fill in several forms for clinical and statistical reasons. Electronic aids are available only for parts of some tasks. The goal should be a multifunctional summary satisfactory for clinical and statistical purposes, most aspects of which are created automatically by a computer system.