[The Development of First Operating Microscopes from Zeiss Jena and Oberkochen to Series Production]. / Die Entwicklung der ersten OP-Mikroskope von Zeiss Jena und Oberkochen bis zur Serienfertigung.

Introduction: The history of the first operating microscopes from Zeiss is often confusing, not painstaking and partly contradictory because of the parallel development of Zeiss Jena (East Germany) and Zeiss Oberkochen (West Germany). Methods: To investigate the early beginnings of the construction of the operating microscopes documents of the Carl Zeiss Archive and the Optical Museum in Jena, the memoirs of Prof. Dr. Rosemarie Albrecht and some relevant publications were used. Results: The development of the first Jena operating microscope was initiated in 1949 by the ENT-physician Prof. Dr. Rosemarie Albrecht in the Soviet occupation zone. The first prototype was tested in the University ENT Clinic, Jena since summer of 1950. On the Leipzig Trade Fair in autumn 1952 the VEB Optik Carl Zeiss Jena presented the first operating microscope nationally and internationally. Series production began in 1953. The first operating microscope of Zeiss Oberkochen was primarily developed by technical designers (H. Littmann) as a colposcope. But in the Carl Zeiss Archive no documents could be found related to the cooperation with gynecologists. 1953 the operating microscope (OPMI 1) came into public and its series production started. From this date on, it was adopted by the otologist Prof. Dr. Horst Ludwig Wullstein to the needs of Otorhinolaryngology. Conclusion: The first Zeiss operating microscope came from Jena. The operating microscope from Zeiss Oberkochen had some advantages for the surgeons and won the competition in the future.

[Chemosensory Evoked Changes of Breathing Pattern During Propofol-induced Sedation]. / Chemosensorisch evozierte Atemänderungen während zweier Propofol-induzierter Sedierungsstadien.

BACKGROUND: The affective valence of an olfactory stimulus will be encoded in its respiratory response. Unpleasant odors shorten the inhalation of the first stimulated breaths in wakefulness and sleep. The aim of the present study was to assess the effekt of intravenous anesthetic propofol on the chemosensory evoked changes of breathing pattern. MATERIAL AND METHODS: 13 ASA 1/2 patients got intranasal chemosensory stimuli (H2S and CO2) by flow-olfactometer during "deep" (EEG-based bispectral analysis, BIS:≤60) and "moderate" (BIS>60) propofol-induced sedation with preserved spontaneous breathing. The duration of the in- and exhalation was analyzed for 5 breaths before and for 2 breaths after the onset of stimulation. RESULTS: During deep sedation respiratory reactions were observed only by CO2 irritation. During moderate sedation respiratory responses were evoked by H2S stimuli, too. In moderate sedation extensions of the inhalations of the first breath after both the unpleasant pure olfactory H2S stimuli and the trigeminal stimuli were more frequent than reductions. CONCLUSION: Olfactory stimuli change the breathing only during moderate sedation, trigeminal stimuli during deep and moderate propofol-induced sedation. In opposite to both wakefulness and sleep the duration of inhalation is often extended by H2S-stimuli during moderate sedation.

Transtracheal ventilation with a novel ejector-based device (Ventrain) in open, partly obstructed, or totally closed upper airways in pigs.

BACKGROUND: Transtracheal access and subsequent jet ventilation are among the last options in a 'cannot intubate-cannot oxygenate' scenario. These interventions may lead to hypercapnia, barotrauma, and haemodynamic failure in the event of an obstructed upper airway. The aim of the present study was to evaluate the efficacy and the haemodynamic effects of the Ventrain, a manually operated ventilation device that provides expiratory ventilation assistance. Transtracheal ventilation was carried out with the Ventrain in different airway scenarios in live pigs, and its performance was compared with a conventional jet ventilator. METHODS: Pigs with open, partly obstructed, or completely closed upper airways were transtracheally ventilated either with the Ventrain or by conventional jet ventilation. Airway pressures, haemodynamic parameters, and blood gases obtained in the different settings were compared. RESULTS: Mean (SD) alveolar minute ventilation as reflected by arterial partial pressure of CO2 was superior with the Ventrain in partly obstructed airways after 6 min in comparison with traditional manual jet ventilation [4.7 (0.19) compared with 7.1 (0.37) kPa], and this was also the case in all simulated airway conditions. At the same time, peak airway pressures were significantly lower and haemodynamic parameters were altered to a lesser extent with the Ventrain. CONCLUSIONS: The results of this study suggest that the Ventrain device can ensure sufficient oxygenation and ventilation through a small-bore transtracheal catheter when the airway is open, partly obstructed, or completely closed. Minute ventilation and avoidance of high airway pressures were superior in comparison with traditional hand-triggered jet ventilation, particularly in the event of complete upper airway obstruction.

The unanticipated difficult intubation: rigid or flexible endoscope?

BACKGROUND: Unanticipated difficult intubation occurs with a frequency between 1.5% and 8.5%. The aim of this study was to compare the use of flexible versus rigid endoscopy in such a patient population, with respect to the preparation time and feasibility of each device. METHODS: During a four-year observational period, 116 patients with unanticipated difficult intubation were managed either with the flexible fiberscope (FFI group, n= 57) or the rigid Bonfils endoscope (RBI group, n= 59) on a randomized basis. RESULTS: The time required for preparing and performing the intubation was significantly shorter in the RBI group: median (IQR) 160 s (118-209 s) as opposed to 229 s (162-326 s) in the FFI group (P=0.001). There were no significant differences with respect to endoscopic visibility or quality of the intubation manoeuvre (P>0.1 each). Causes of unanticipated difficult intubation were mainly as follows: restricted movement of the head and neck (39.7%), a Mallampati class > 2 (35.3%), a short neck (31%) or a thyromental distance < or = 5 cm (28.4%). Postoperative complications associated with the intubation maneuver included slight bleeding (FFI = 8.8% vs RBI = 8.5%; NS), technical problems (12.3 vs 10.2%, NS), hoarseness (15.8 vs 15.3%, P=0.946) and dysphagia (5.3 vs 16.9%, P=0.070). CONCLUSION: Both endoscopic techniques enable quick and safe intubation. The Bonfils method could be the method of choice in cases of already relaxed patients with unanticipated difficult conventional laryngoscopy, presuming that the anaesthetist is familiar with this technique. Because the clinical re-evaluation for possible predictors of difficult intubation revealed no unknown new factors, the preoperative examination for anatomical peculiarities and being aware are the best protection against unanticipated intubation problems.

[Perforation of the hypopharynx as a rare life-threatening complication of endotracheal intubation]. / Die Perforation des Hypopharynx als seltene, lebensbedrohliche Komplikation der endotrachealen Intubation.

BACKGROUND: Endotracheal intubation is regarded as the gold standard technique to secure the airway with a low complication rate, however, perforating tracheal or esophageal injuries are rare but severe complications. MATERIALS AND METHODS: Two cases of hypopharyngeal perforation after intubation are presented and discussed. RESULTS: While intubation of the first patient was anticipated to be difficult, the second patient did not present any risk factors. One patient developed a typical clinical pattern of difficult swallowing, soft tissue emphysema of the neck, pyrexia, and leukocytosis. The other initially showed minor symptoms but increasing difficulties in swallowing led to the diagnosis of a retropharyngeal abscess. A subsequent acute airway obstruction required emergency invasive airway access. In both cases surgical intervention in combination with antibiotic therapy resulted in complete healing. CONCLUSIONS: Physicians performing endotracheal intubation or dealing with patients after intubation, should be aware of the clinical symptoms because only early diagnosis and therapy can prevent development of mediastinitis. In "cannot intubate-cannot ventilate" situations, wide bore transtracheal airway access under local anaesthesia and spontaneous breathing should have priority and temporary tracheotomy should also be considered. To prevent hypopharyngeal injury a thorough evaluation of the "difficult airway" and the atraumatic performance of direct laryngoscopy and endotracheal intubation are mandatory.

[Diagnostic and therapeutic procedure for spontaneous emphysema of the neck and mediastinum]. / Diagnostisches und therapeutisches Vorgehen beim spontanen Emphysem der Halsweichteile und des Mediastinums.

BACKGROUND: Emphysema without any etiological indices from the history represents a diagnostic and therapeutic challenge. PATIENT COLLECTIVE: Over the last 5 years, we treated four patients (three male, one female; aged 3-29 years) with cervical and/or mediastinal emphysema of unknown cause. RESULTS: Two young men with cervical emphysema were observed and received prophylactic antibiotic treatment. After involution of the emphysema, we performed an endoscopy which revealed no abnormalities. A female patient and a 3-year-old boy had a history of coughing and a query history of foreign body ingestion before the appearance of the emphysema. The immediate endoscopies were without pathologic findings. All patients recovered completely without any complications or recurrences. CONCLUSIONS: If there is no indication for a foreign body or a trauma in the history or in radiological imaging, endoscopy of the airways and the upper digestive tract should follow when the emphysema has subsided. The aim is to avoid any further spread of the emphysema and of pathogens. If there is a history of a foreign body or trauma, an immediate endoscopy is indicated.

Comparison of transcutaneous and endtidal CO2-monitoring for rigid bronchoscopy during high-frequency jet ventilation.

OBJECTIVE: To compare endtidal and transcutaneous respiratory monitoring of high-frequency jet ventilation (HFJV) in rigid bronchoscopy. Both techniques provide a noninvasive measurement of pCO2. METHODS: High-frequency jet ventilation was applied via a rigid bronchoscope. Driving pressure (DP) was initially adapted to ensure normal ventilation. It was then changed twice by +/- 30% from the initial value. Endtidal and transcutaneous data were compared with arterial blood gas monitoring (ABG). RESULTS: Results were analyzed separately for the time just after changing the driving pressure (10 min) and the remaining time until the next change of the driving pressure (4 min). The first part was called the dynamic phase, and the second part the steady-state phase. Correlation coefficient between endtidal capnography and ABG was 0.96 for the steady state and 0.94 for the dynamic phase, respectively. Bland-Altman analysis revealed a bias of -0.21 kPa with limits of agreement (LOA) 1.63 kPa for the steady state and -0.25 kPa, 2.08 kPa for the dynamic phase, respectively. Correlation coefficient between transcutaneous monitoring and ABG for the steady state phase was 0.83, and was 0.72 for the dynamic phase. Bland-Altman analysis resulted in a bias of -0.89 kPa with LOA - 3.84 kPa during steady state and 0.92 kPa, 4.06 kPa for the dynamic phase, respectively. CONCLUSION: Endtidal capnography offers accurate respiratory monitoring of HFJV. Transcutaneous monitoring showed a good correlation to ABG only during steady-state conditions. For the dynamic phase the accuracy was significantly lower. Thus, we cannot recommend transcutaneous respiratory monitoring for the specific indication of rigid bronchoscopy using HFJV.

[The incidence of microlaryngoscopy associated complications]. / Inzidenz spatelbedingter Nebenwirkungen der Mikrolaryngoskopie.

BACKGROUND: The frequency of local and cardiovascular side effects of microlaryngoscopy is generally underestimated. There are no data available in the literature from recent and prospective clinical trials. PATIENTS AND METHODS: We examined 81 patients between 03/1998 and 03/2000 who underwent microlaryngoscopy in our department. This was done following a standard protocol before, during and after surgery. Side effects of endotracheal intubation were avoided by using supraglottic jet-ventilation. RESULTS: In 79% of our cases we encountered side effects due to the microlaryngoscopic procedure.86% of them were reversible lesions,hematomas and edemas of the mucous membranes or mild cardiovascular dysregulations. In two cases there was a dental complication (one fracture, one dislocation), and seven cases of moderate hemodynamic effects were noted. CONCLUSIONS: The incidence of tissue damage caused by microlaryngoscopic endoscopes is much higher than commonly assumed in clinical practice. This has to be explained to the patient when obtaining his written consent to a certain microlaryngoscopic procedure and to be considered during the postoperative follow up.The consequent use of tooth protection and a good control of muscle relaxation and analgesia can be effective in preventing side effects.

[Prognostic value of a screening test for difficult microlaryngoscopy]. / Prognostische Wertigkeit von Screeningtests für die erschwerte Mikrolaryngoskopie.

BACKGROUND: Several screening methods for the prediction of a difficult endotracheal intubation such as the test by Patil or the Mallampati-Score have been described. The incidence of difficult microlaryngoscopic procedures and the prognostic value of those screening tests for their prediction has not been investigated. PATIENTS AND METHODS: We examined 81 patients with mainly benign conditions of the larynx in a prospective study to evaluate the maximal overview of the glottis gained during microlaryngoscopy under supraglottic jetventilation. We used a specially designed ruler to measure the length of the invisible portion of the glottis. RESULTS: The incidence of a difficult microlaryngoscopy was 4.9%. All employed screening scores did not reach a satisfactory positive predictive value (PPV). The routine indirect laryngoscopy with phonation had the highest PPV (50%) of all tests. CONCLUSION: Therefore an impossible indirect laryngoscopy can be regarded as a warning sign for a difficult microlaryngoscopic procedure. Summation-scores like the Arné Multivariate Risk Index or the use of check lists (Benumof) may improve the predictive value of preoperative screening.

[Transtracheal oxygenation in respiratory tract obstruction from a hypopharyngeal tumor]. / Transtracheale Oxygenierung bei Atemwegsverlegung durch einen Hypopharynxtumor.

A 42-year-old male with a history of chronic alcoholism was admitted to the department of otolaryngology with acute respiratory insufficiency and generalised cyanosis due to a respiratory obstruction by a large tumour of the hypopharynx. Because of the size and location of the tumour and the risk of bleeding, orotracheal intubation by direct laryngoscopy was considered almost impossible. To improve oxygenation cricothyroidal punction and oxygen insufflation was done immediately and SpO2 increased from 56% to 82%. Awake fiberoptic nasotracheal intubation was performed under topical anaesthesia, then general anaesthesia was induced and controlled ventilation was started. After surgical tracheotomy the patient was transferred to an intensive care unit and 12 h later the patient was discharged from the ICU.

Catalytic methanol oxidation over copper: observation of reaction-induced nanoscale restructuring by means of in situ time-resolved X-ray absorption spectroscopy

The catalytically active copper phase for the partial oxidation of methanol is studied by means of time-resolved extended X-ray absorption fine structure (EXAFS) spectroscopy combined with the detection of the catalytic turnover. It is found that the active form of the copper is a strained nanocrystalline form of the metal. The metal is no longer made up from large crystallites but contains a defect structure in which oxygen is already intercalated.

[Value of aspiration of tracheal secretions and bronchoalveolar lavage in diagnosis of nosocomial pneumonia in ventilated patients]. / Stellenwert von trachealer Sekret-Aspiration und bronchoalveolärer Lavage in der Diagnostik nosokomialer Pneumonien bei beatmeten Patienten.

The diagnostic value of endotracheal aspirates with quantitative assessment and bronchoalveolar lavage (BAL) was investigated in 104 mechanically ventilated patients in an anaesthesiologic/surgical intensive care unit. Patients were either considered as "pneumonia positive" (77 patients) according to clinical, radiological or laboratory criteria or "pneumonia negative" (27 patients). Using a threshold of 10(5) colony forming units (cfu) per ml for endotracheal aspirates and 10(4) cfu/ml for BAL-fluid, the results were similar for both techniques (sensitivity 74% and 77% respectively; specifity 63%). In our investigation, in 80% of the cases microbial growth was observed in either both or neither of the techniques. Therefore 20% of the patients had positive results in only one of the two diagnostic procedures. As a consequence of the presented study, quantitative assessment of endotracheal aspirates as a cost-effective, low-invasive and simple technique could be helpful in diagnosing nosocomial pneumonia in mechanically ventilated patients. Performance of BAL is indicated in patients with clinical signs of nosocomial pneumonia and negative results in endotracheal aspirates (< 10(5) cfu/ml). Nevertheless, diagnostic uncertainty will remain in about 15% of all cases, even when both techniques are applied. The primary use of invasive bronchoscopic techniques, such as BAL, in diagnosis of nosocomial pneumonia has to be considered critically.

Role of fiberoptic bronchoscopy in conjunction with the use of double-lumen tubes for thoracic anesthesia: a prospective study.

BACKGROUND: Fiberoptic bronchoscopy has been recommended to verify the position of double-lumen tubes (DLT), but this remains controversial. The authors studied the role of bronchoscopy for placing and monitoring right- and left-sided DLTs after blind intubation and after positioning the patient. METHODS: Two hundred patients having thoracic surgery requiring DLT insertion were prospectively studied. "Blind" tracheal intubations were done with 163 left-sided and 37 right-sided disposable polyvinyl chloride Robertshaw tubes. Bronchoscopy was performed by a different anesthesiologist after intubation and conventional clinical verification of correct placement and after patient positioning for thoracotomy. A DLT was considered malpositioned when it had to be moved >0.5 cm to correct its position. Critical malpositions were those that might have affected patient safety or influenced the surgical procedure if left uncorrected. RESULTS: After "blind" DLT intubation, clinical evidence of malpositioning was found in 28 patients. This was confirmed by fiberoptic assessment. In 172 patients in whom placement was judged correct by clinical assessment, malpositioning was detected by bronchoscopy in 79 cases, 25 of which were critical. After patient positioning, DLTs were found to be displaced in 93 patients, 48 of which were critical. Right-sided DLTs were significantly more likely to be malpositioned than were left-sided DLTs. Two complications were related to unsatisfactory lung separation in the 200 patients studied. CONCLUSIONS: After blind intubation and patient positioning, more than one third of DLTs required repositioning. Routine bronchoscopy is therefore recommended after intubation and after patient positioning.