Der Anaesthesist
-
Clinical Trial
[The difficult intubation. The value of BURP and 3 predictive tests of difficult intubation].
The value of BURP (= backwards-upwards-rightwards-pressure of the larynx) was tested as a improvement of the visualisation of the larynx. Simultaneously we wanted to assess the value of different predictive tests of a difficult intubation, which are easy to perform as bedside tests. ⋯ BURP is a valuable method for rendering the majority of difficult laryngoscopies into easy ones. It is very easy to learn and does not need any additional equipment. Three commonly used and recommended predictive tests of the difficult intubation proofed to be of little use in clinical practice.
-
Comparative Study
[Causes of failure and dangers in the use of motor driven infusion pumps. Accidental closure of the infusion system].
Syringe drivers are used in anaesthetics, intensive care and emergency medicine to deliver small volumes of highly potent drugs with continuous, constant and reproducible flow. For early recognition of interruptions of the drug delivery caused by occlusion of the infusion system, an alarm is triggered as soon as the system pressure exceeds a certain limit. The sensitivity of this alarm depends on the flow rate, type-specific cut-off pressure and the elastic parameters of the infusion system. The sudden release of pressure built up in the system after occlusion occurred can cause delivery of an uncontrolled drug bolus and hence an additional hazard. ⋯ Unidentified occlusions of the system cause grave malfunctioning of syringe drivers. While applying highly potent drugs, the discontinuation of drug delivery with subsequent bolus application can cause vital danger to the patient. As a result of the significant time delays in the pressure alarms, the devices tested do not provide sufficient protection against unrecognized system occlusion. Syringe drivers with adjustable alarm pressure can be set close to the actual infusion pressure. A further important point is that one should aim at a reduction in the elastic properties of the infusion set because of the great impact on alarm delay and bolus volume.
-
General cardiovascular properties of ketamine: "In vitro", ketamine has moderate negative inotropic effects. "In vivo", a significant central sympathomimetic action with consecutive hemodynamic effects is dominant. The sympathomimetic potency of ketamine is one of the most significant pharmacological features of the substance with direct clinical implications. Monoanaesthesia with S-(+)-ketamine: After application of racemic ketamine or S(+)-ketamine as well, identic and significant increases in plasma catecholamines, arterial pressure and heart rate are observed. This outstanding sympathomimetic action is beneficial in induction of patients with shock or asthmatic state. TIVA and analgosedation with S-(+)-ketamine and midazolam: The sympathomimetic effect of S(+)-ketamine, and racemic ketamine as well, is mitigated by midazolam. Nevertheless, significant increases in heart rate and arteriel pressure might be observed. Clinical use of the combination is common in short procedures like reposition maneuvers. Of greater importance is the use for analgosedation in patients with cardiovascular instability, particularly in patients with exogenous catecholamine demand. TIVA and analgosedation with S-(+)-ketamine and propofol: When S(+)-ketamine is combined with propofol, the sympatholytic effects of propofol are counteracted by S(+)-ketamine, and stable hemodynamic conditions are presented. This combination seems useful for TIVA in patients with hypotonic dysregulation or endocrine deficits like hypothyreosis and adrenal insufficiency. Furthermore, analgosedation with S(+)-ketamine and propofol is advantageous, when rapid recovery is necessary and negative circulatory effects should be avoided. ⋯ Sympathoadrenergic and hemodynamic effects of S(+)-ketamine and racemic ketamine are generally identical. The distinctest action is observed, when S(+)-ketamine is used as a monoanaesthetic. In combination with midazolam, a significant reduction is achieved. In combination with propofol, the sympatholytic effects of this hypnotic agent are compensated by S(+)-ketamine. With respect to sympathoadrenergic and hemodynamic reactions, the clinical position of S(+)-ketamine is unchanged. Nevertheless, a significant clinical progress can be expected due to improved recovery and reduced substance load, when racemic ketamine is replaced by S(+)-ketamine.
-
The pharmacological profile of ketamine: Until recently, clinically available ketamine was a racemic mixture containing equal amounts of two enantiomers, (S)- and (R)-ketamine. The pharmacological profile of racemic ketamine is characterized by the so called dissociative anesthetic state and profound sympathomimetic properties. Among the different sites of action, N-methyl-D-aspartate (NMDA)-receptor antagonism is considered to be the most important neuropharmacological mechanism of ketamine. ⋯ In combination with midazolam and propofol, excellent control of analgosedation was found, making both combinations suitable for situations in which repeated neurological assessment of patients is necessary. In emergency and disaster medicine, (S)-ketamine is of outstanding importance because of its minimal logistic requirements, the chance for intramuscular administration and the broad range of use for analgesia, anaesthesia and analgosedation as well. Further perspectives of (S)-ketamine may be the treatment of chronic pain and the assumed neuroprotective action of the substance.