Biomedical subjects

Andreas Gerber

Publications and source records attributed to Andreas Gerber.

9 recordsLinked to original sources

PubMed2006

Next-generation applications in healthcare digital libraries using semantic service composition and coordination.

Healthcare digital libraries (DLs) increasingly make use of dedicated services to access functionality and/or data. Semantic (web) services enhance single services and facilitate compound services, thereby supporting advanced applications on top of a DL. The traditional process management approach tends to focus on process definition at build time rather than on actual service events in run time, and to anticipate failures in order to define appropriate strategies. This paper presents a novel approach where service coordination is distributed among a set of agents. A dedicated component plans compound semantic services on demand for a particular application. In failure, the planner is reinvoked to define contin- gency strategies. Finally, matchmaking is effected at runtime by choosing the appropriate service provider. These combined technologies will provide key support for highly flexible next-generation DL applications. Such technologies are under development within CASCOM.

Information Storage and Retrieval↗

PubMed2005

Evidence-based medicine is rooted in Protestant exegesis.

Evidence-based medicine (EbM) has been practised for about a decade now. Until now, it has generally been accepted that EbM has its roots in medical thinking of mid-19th century France. Due to the startling fact that France never was a centre of EbM, historical tradition was reconsidered. Since EbM has mainly been flourishing in Protestant countries, a qualitative historical investigation was conducted according to the approach of Max Weber's "The Protestant Ethics". Thus, it could be shown that there are three major prerequisites for EbM to evolve apart from current technical developments, such as the computer and the internet: (1) historical critical exegesis functioned as a methodology to balance contradictory passages; (2) both an equality based relationship among physicians and a Protestant concept that lay people are considered equal in the theologic debate were fundamental to EbM as a new approach of medical thinking; (3) mostly nationally funded health care systems are prone to practise EbM as they are obliged to provide health care which is both fair in access and allocation to the whole population. Against the background of historical exegesis, it has to be taken into account that EbM implies a twist in medicine towards a concept of textual criticism rather than the mere introduction of statistics. Moreover, it both relies upon and enhances a more equal relationship between physicians.

Christianity↗

PubMed2004

The Microcuff tube allows a longer time interval until unsafe cuff pressures are reached in children.

PURPOSE: To compare cuff pressures during nitrous oxide exposure in the new Microcuff pediatric tracheal tube (MPT) with ultrathin high volume - low pressure polyurethane cuff to a tube with a standard polyvinyl chloride (PVC) cuff. METHODS: With approval of the local Ethics Committee, 30 pediatric patients requiring tracheal intubation [tube size internal diameter (ID) 4.0 mm, or ID 7.0 mm) were included. Patients were randomly divided in three groups: A) MPT, baseline cuff pressure 20 cm H(2)O; B) PVC, baseline cuff pressure 20 cm H(2)O; and C) MPT, baseline cuff pressure set to sealing pressure. Anesthesia technique and ventilator settings were standardized. The time required for cuff pressure to increase to 25 cm H(2)O was recorded and pressure reduced to baseline. The number of gas removals required during the first hour was noted. Data are median (range). Groups were compared by the Kruskal-Wallis test (P < 0.05). RESULTS: There were no differences between groups in patient characteristics. PVC and MPT cuffs inflated to a baseline pressure of 20 cm H(2)O were similar regarding the time to first removal of gas [A: nine minutes (4-24), B: eight minutes (4-46)], and number of removals required [A: four (2-6), B: three (1-5)]. In MPT with baseline pressure set to sealing pressure [10 cm H(2)O (8-14)] time to first gas removal and number of removals were significantly less (P < 0.05). CONCLUSION: When baseline inflation pressure was set at 20 cm H(2)O, cuff pressure increased similarly in MPT and PVC tubes. When inflated just to sealing pressure, the MPT allowed a longer time interval until the upper limit of 25 cm H(2)O was reached.

Adolescent↗

PubMed2003

Fluid leakage past tracheal tube cuffs: evaluation of the new Microcuff endotracheal tube.

OBJECTIVE: This study compared the recently introduced Microcuff endotracheal tube HVLP ICU featuring an ultrathin (7-microm) polyurethane cuff membrane with endotracheal tubes from different manufacturers regarding fluid leakage past the tube cuff. DESIGN: In vitro setup. MEASUREMENTS AND RESULTS: The following endotracheal tubes (ID 7.5 mm) were compared: Mallinckrodt HiLo, Microcuff HVLP ICU, Portex Profile Soft Seal, Rüsch Super Safety Clear, and Sheridan CF. A vertical PVC trachea model (ID 20 mm) was intubated, and cuffs were inflated to 10, 15, 20, 25, 30, and 60 cmH2O. Colored water (5 ml) was added to the top of the cuff. The amount of leaked fluid past the tube cuff within 5, 10, and 60 min was recorded. Experiments were performed four times using two examples of each tube brand. Fluid leakage past tube cuffs occurred in all conventional endotracheal tubes at cuff pressures from 10 to 60 cmH2O. In the Microcuff tube cuff pressure fluid leakage was observed within 10 min only at 10 cmH2O. Results with the Microcuff tube were significantly better than all other tube brands at cuff pressures of 10-30 cmH2O. CONCLUSIONS: Within the acceptable upper limit for tracheal cuff pressure (25-30 cmH2O) the Microcuff endotracheal tube was the only one of the tested tubes to prevent fluid leakage in our in vitro setup. In vivo studies are required to confirm these findings.

Equipment Design↗

PubMed2003

Nitrous oxide does not affect automated air tonometry in children.

PURPOSE: To evaluate the effects of nitrous oxide on automated air tonometry in the clinical setting. MATERIAL AND METHODS: With approval of the Hospital Ethical Committee and after obtaining informed parental consent, an 8-F tonometry catheter was inserted orogastrically in ten children aged one to three years scheduled for elective surgery with combined regional and general anesthesia. A standardized general anesthesia technique with tracheal intubation was used in all patients and consisted of sevoflurane in oxygen/nitrous oxide (30%/70%; n = 5 patients) or in oxygen/air (FIO(2) 0.3; n = 5 patients). After obtaining steady state gastric CO(2) values (PrCO(2)), fresh gas mixtures were rapidly changed from oxygen/nitrous oxide to oxygen/air (A) or vice versa (B). In addition, balloon pressures were recorded using a pressure transducer. Measurements were performed at intervals of ten minutes with recording of balloon pressures, end-tidal CO(2) (PETCO(2)) and PrCO(2) values. Pr-ETCO(2)-gap were calculated to eliminate influences of changes in PaCO(2). RESULTS: Changing the fresh gas mixture from N(2)O/O(2) to O(2)/air resulted in a decrease of balloon pressure of -10.4% (113.4 +/- 14.7 mmHg to 101.6 +/- 25.0 mmHg). Changing the fresh gas mixture from O(2)/air to N(2)O/O(2) resulted in an increase of balloon pressures of 6.4% (107.6 +/- 19.3 mmHg to 114.0 +/- 20.3 mmHg). During both fresh gas exchange experiments no significant changes (> 0.2 kPa) in calculated Pr-ETCO(2)-gaps were observed. CONCLUSIONS: Based on our in vivo data, nitrous oxide during general anesthesia can be used with automated air tonometry and does not affect air tonometric PrCO(2) reading in clinical practice.

Anesthesia, General↗

PubMed2003

Video-enhanced visualization of the larynx and intubation with the Bullard laryngoscope--equipment report.

PURPOSE: A simple technical solution is presented to provide video transmission from the tip of a Bullard laryngoscope to a bedside video display, while the operator is still able to look through the viewing ocular of the Bullard laryngoscope during tracheal intubation. EQUIPMENT: This is achieved by insertion of an ultrathin fibreoptic video-endoscopic system into the working channel of the Bullard laryngoscope. Thereby the view from the distal blade tip is transmitted to a bedside monitor, without interfering with the use of the Bullards laryngoscope's original eyepiece. The presented technical solution allows video transmission without considerable additional weight normally associated with attaching video endoscopy cameras, light and camera cables to endoscopic devices. Thus, the Bullard laryngoscope remains lightweight and easy to maneuver. A screw-threaded adapter with a side-port is proposed to prevent displacement of the fibreoptic cable while still allowing application of oxygen. CONCLUSION: Experience and skills with tracheal intubation using the presented video-enhanced Bullard laryngoscope can be achieved in the originally intended way, while the supervisor or attending viewers can follow the tracheal intubation procedure on the video display.

Computer Terminals↗

PubMed2003

Measurement of cerebral oxygenation state in anaesthetized children using the INVOS 5100 cerebral oximeter.

BACKGROUND: Near-infrared spectroscopy is a developing technique for monitoring cerebral oxygenation during anaesthesia. The aim of this study was to evaluate absolute values of cerebral oxygenation during stable anaesthesia conditions in otherwise healthy children using the recently introduced INVOS 5100 cerebral oximeter with a paediatric and adult sensor and to compare them with values obtained from the NIRO 300 oximeter. METHODS: Thirty paediatric surgical patients (aged 0.23-15.97 years) were studied during general anaesthesia with tracheal intubation and controlled ventilation. Comparative measurements of cerebral oxygenation were performed on the forehead with two probes within 10 min under stable cardiorespiratory and anaesthesia conditions. Cerebral oxygenation values (rSO2) obtained from the paediatric and adult INVOS 5100 sensors were compared with the tissue oxygenation index (TOI) obtained from the NIRO 300 cerebral oximeter using 4- and 5-cm emitter-detector separation. RESULTS: Cerebral rSO2 values and the TOI values both showed a large range of cerebral oxygenation in the children studied (rSO2: 59-95%, TOI: 48-85%). Cerebral rSO2 values measured by the INVOS 5100, particularly with the paediatric sensor, were significantly higher than the TOI values obtained from the NIRO 300 (P < 0.0001). Agreement between the INVOS and NIRO oximeter was poor. CONCLUSION: The large range and the poor agreement of cerebral oxygenation values between the two oximeters makes it difficult to define a normal value. Cerebral oxygenation readings by these monitors, based on one single point measurement during anaesthesia, should be viewed with caution. Actually, there may be little indication for routine use of such monitoring during general anaesthesia.

Adolescent↗

PubMed2002

Tracheal intubation in children with Morquio syndrome using the angulated video-intubation laryngoscope.

PURPOSE: There are a number of syndromes with proven or suspected instability of the cervical spine especially in pediatric patients. It is a challenge for the anesthesiologist to intubate these patients with as little movement of the cervical spine as possible. A new device to facilitate this task is the angulated video-intubation laryngoscope (AVIL). CLINICAL FEATURES: The AVIL is a curved endoscopic intubation laryngoscope with angulated distal tip. The video-view from the distal blade tip improves glottic visualization during difficult direct laryngoscopy. We report three sisters with Morquio syndrome scheduled for otorhinolaryngology surgery the same day. Two of them had radiologically suspected cervical spine instability. Tracheal intubation was planned with careful direct laryngoscopy under manual in-line stabilization of the neck and head by an assistant. Direct visualization of the larynx using a Miller blade No. 2 was impaired in two of the three children in whom the cervical spine was immobilized. They were both successfully intubated under endoscopic control using the AVIL. CONCLUSION: The AVIL may become a helpful device to aid endotracheal intubation in patients when cervical spine immobilization impairs direct laryngoscopy.

Child↗

PubMed2002

Long-term results after acute percutaneous transluminal coronary angioplasty in acute myocardial infarction and cardiogenic shock.

The aim of this study was to determine the long-term outcome in unselected, consecutive patients after acute percutaneous transluminal angioplasty (PTCA) for acute myocardial infarction (AMI) complicated by cardiogenic shock. This involved a follow-up study from a prospectively conducted patient registry in a tertiary referral center. A total of 59 patients (10 female/49 male; median age 62 years (32-91)) with percutaneous transluminal cardiac interventions in primary cardiogenic shock were identified between January 1995 and January 2000. Twenty-two patients (37%) had been resuscitated successfully before intervention. The in-hospital mortality of shock patients was 36% (n=21, median age 68 (47-84)). The median follow-up of survivors was 18.1 (7-57.3) months, during which three further patients died (8%; two because of sudden cardiac deaths, one because of acute reinfarction). Achievement of thrombolysis in myocardial infarction (TIMI) flow III after acute PTCA (84% in survivors vs. 38% in non-survivors; P<0.001) and the absence of the left main coronary artery (3% survivors vs. 29% non-survivors; P=0.003) as culprit lesion in patients with cardiogenic shock was strongly associated with an improved survival rate. A second cardiac intervention was performed in seven patients (18%). Overall functional capacity of shock survivors was good. At final follow-up, 80% of the survivors were completely asymptomatic. One patient had angina pectoris NYHA II, five patients dyspnoea NYHA class II. Exercise stress-test was performed in 24 of the 38 surviving patients, median exercise capacity was 100% (range 55-113%) of the age adjusted predicted value. In unselected patients with cardiogenic shock due to AMI, treatment with acute PTCA resulted in an in-hospital mortality of 36%, low late mortality and good functional capacity in long-term survivors. TIMI flow grade III after acute PTCA in patients with acute myocardial infarction complicated by cardiogenic shock was strongly associated with an improved survival rate whereas the left main coronary artery as culprit lesion was associated with worse outcome.

Adult↗