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Biomedical subjects

W Maleck

Publications and source records attributed to W Maleck.

32 records · Page 2Linked to original sources

[Stress free anesthesia induction ZESTRANI (ZEro STRess ANesthesia Induction) in Göttingen minipigs. An experimental method].

The Göttingen Mini-pig is a popular laboratory animal, that is used i.a. in experimental surgery and anaesthesia. For ethical and scientific reasons it is mandatory to minimize the stress the laboratory animals are exposed to. The presented stress-free experimental anaesthesia induction (ZESTRANI) is based on innovative means to achieve adequate analgesia using different substances appropriate for the animal's state of consciousness. Markedly lower heart rates and mean arterial pressures are seen when the ZESTRANI-method is used as compared retrospectively to the previously used "conventional" anaesthesia induction. With the ZESTRANI method no "fight or flight"-reactions are seen.

Anesthesia, General↗

Oximetry for amniotic fluid embolism detection in mini-pigs: tail or snout?

The continuous, non-invasive real-time monitoring of arterial oxygenation (pulse oximetry) has become a standard of care in both human and veterinary medicine. It allows reliable, simple and inexpensive assessment of the arterial oxygenation status. In pigs, commonly used sites for oximetry-probe placement are the ear, snout or tongue, while more recently the 'pig-tail oximetry' has been suggested. In a study regarding the coagulation system during amniotic fluid embolism (AFE) in mini-pigs, we compared tail and snout for oximetry-probe placement and compared them with the 'gold standard': blood-gas analysis (BGA). In both the AFE group and the control group, the tail measurements were slightly lower and the snout measurements were slightly higher than the BGA results. In the experimental model used, both tail and snout measurements were able to detect a temporary desaturation immediately after amniotic fluid embolism (AFE). Blood-gas analysis (BGA) performed on blood drawn from a large artery missed the event. Clinically, there is no significant difference between snout and tail as oximetry-probe placement sites: both are reliable oximetry sites in mini-pigs.

Animals↗

[Preclinical control of intubation and artificial respiration. Animal experiment and literature review].

Oesophageal malposition of an endotracheal tube is among the leading causes of anaesthesia incidents. While clinical manoeuvres for detection of tube malposition are unreliable, monitoring (i.e. capnography) can prevent such incidents. The problem is particularly important in prehospital care, where capnography is not (yet) widely available. We tested three devices used for differentiating oesophageal from endotracheal intubation: 1. Non-CO2-dependent Oesophageal Detector Device (ODD) as described by Pollard and Wee, 2. Semi-quantitative chemical disposable capnometer EasyCAP (Nellcor), 3. Non-quantitative infrared miniaturised capnometer MiniCAP (MSA). METHODS. 50 anaesthetised minipigs were intubated with a Magill tube. An identical additional tube was placed in the oesophagus. The cuffs of both tubes were inflated. Unexperienced personnel (students, laboratory technicians) were asked to determine the position of one of the tubes by using one of the devices according to the randomisation plan. The decision had to be taken within 30 s. Using the ODD, the proband first injected 100 ml air into the lung (or stomach) and then tried to aspirate the same volume. EasyCAP and MiniCAP were used according to manuals. RESULTS. Each device was used 25 times with a tracheal tube and 25 times with an oesophageal tube. All tube position identifications were correct. When ventilating the oesophagus/stomach for capnometric control, regurgitation into the tube occurred six times (five times with the EasyCAP and once with the MiniCAP). In these cases, the decision was based on this occurrence and not on the display of the device. While using the ODD no regurgitation occurred. CONCLUSION. These devices are useful for preclinical practice. According to the literature and our experience, the ODD is superior for the initial control of tube position, especially in cardiac arrest. Capnometry is needed, however, for continuous control of ventilation.

Anesthesiology↗

Carbon monoxide and nonquantitative carbon dioxide detection.

INTRODUCTION: The capnometric demonstration of end-tidal carbon dioxide (CO2) is a reliable method of differentiating between a correct endotracheal tube position and an accidental misplacement of the tube into the esophagus. Recently, several CO2 detectors have been introduced for monitoring end-tidal CO2 in the "out-of-hospital" setting, where quantitative capnometry with capnography is not yet available. HYPOTHESIS: These devices are not influenced by carbon monoxide (CO) present in lethal concentration. METHODS: A heated (37 degrees C) 2.3 L reservoir bag filled one-third full with water (representing the stomach in esophageal misintubation) was machine ventilated (tidal volume: 450 ml; frequency: 16/min) with the following mixtures for three minutes each: 1) 95% O2, 5% CO; 2) 45% O2, 5% CO, 50% N2O; and 3) 44% O2, 5% CO, 50% N2O, 1% halothane. The presence of end-tidal CO2 was monitored with each of the following devices: 1) MiniCAP III CO2 Detector; 2) StatCAP CO2 Detector; 3) EasyCAP CO2 Detector; 4) PediCAP CO2 Detector; and 5) Colibri CO2 Detector. RESULTS: In none of the cases was the presence of CO2 signaled by the detector. CONCLUSION: The presence of 5% CO does not interfere with infrared spectrometry detection (MiniCAP and StatCAP) or chemical detection (EasyCAP, PediCAP, and Colibri) of CO2. The devices can be used safely in patients with CO poisoning for monitoring of endotracheal tube position.

Capnography↗

Sonomatic confirmation of tracheal intubation using the SCOTI.

This study compares the performance of two commercially available devices (Ambu TubeChek and SCOTI) in establishing endotracheal (ET) tube position (oesophageal vs. tracheal) in a mannequin and in miniature pigs. The Ambu TubeChek is a syringe-type, Oesophageal Detector Device (ODD) that fits to the endotracheal tube connector. Air is aspirated easily from the rigid trachea, but not from the collapsing esophagus. The Sonomatic Confirmation of Tracheal Intubation device (SCOTI) is a lightweight battery-powered, sonomatic device. It emits sound waves into the tube and analyzes the reflection. The SCOTI purports to enable a user-independent and carbon-dioxide-independent assessment of tube position following intubation. Intubation followed by tube position assessment with Ambu TubeChek (ODD) was significantly faster and easier with the ODD than with the SCOTI. The SCOTI cannot differentiate tracheal from oesophageal ET-tube position in mini-pigs. In situations in which capnometry is not available or the CO2 production and transport are compromised (CPR), we recommend the use of an Oesophageal Detector Device (ODD) rather than the SOCTI.

Animals↗