Der Anaesthesist
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Despite the fact that neonates and infants are not capable of expressing their subjective pain sensations, it has become clear that they do perceive nociception, as pain correlates to hormonal, metabolic, immune, and cardiovascular changes. New findings support the notion that repetitive painful stimuli result in long term psycho-physiological effects with ensuing decreased attentiveness and orientation, poor regulation of behavioral state and motor processes, increase in irritability as well as an altered pattern of feeding and sleeping. These sequelae of repetitive painful experiences with an increase in sensitization of sensory afferent input supports the view of a sufficient analgesia during all kinds of painful procedures in the preterm and neonate. ⋯ Sequelae of such differences are a more pronounced respiratory depression, often due to muscular rigidity, and bradycardia after which a full analgesic effect takes place. Despite such potential drawbacks, opioids are still the best choice as they sufficiently block nociceptive afferent input and when compared to other anesthetics, they show the least cardiovascular changes. One, however, has to bear in mind that dosing is done according to effect and not to body weight while potential side effects are most prominent in the preterm infant.
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The undecapeptide substance P is expressed by primary afferent neurons where it is considered to be a cotransmitter of other peptides and glutamate. Since it is predominantly found in sensory neurons with unmyelinated fibres (C-fibres), substance P has long been thought to be a "pain transmitter". Following stimulation of nociceptive afferents, substance P is released in the spinal cord and substance P-mediated transmission is primarily brought about by tachykinin NK1 receptors. ⋯ The hyperalgesic role of substance P has been corroborated by the sensory deficits seen in substance P and NK1 receptor knockout mice. However, the concept that NK1 receptor antagonists would represent a novel class of analgesic drugs, as suggested by the preclinical studies, has not been borne out by the clinical trials that have been reported thus far. This article offers an overview of those hyperalgesic conditions in which NK1 receptor antagonists may be of therapeutic value and discusses possible reasons for the discrepancies between preclinical and clinical trials with NK1 receptor antagonists.
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Clinical Trial
[Hemodynamic, endocrinological and psychological investigations on subjects during helicopter flights].
The emergency transport in an ambulance can be a considerable physical and psychological stress for the patient. In this article we report on a stress test with 23 volunteers transported in an emergency helicopter. ⋯ The stress situation is caused by fear of the flight, that cannot be objectively justified. The relatively low stress induction by helicopter transportation might be an indication that there should be more patient transport with modern helicopters, especially for non-trauma patients. This subject deserves further investigation.
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Case Reports
[Postoperative morphine excess or rational therapy? An exceptional case of applying the morphine equivalent].
We report on a 51-year-old female with a 7 year history of breast cancer. In August 2000 surgical replacement of the 8th thoracic vertebra was performed. From November 2000 the patient developed progressive pain, due to additional spine metastases, leading to pain therapy (according to the patient record) as follows: MST 320 mg oral 4 times daily, Durogesic 100 micrograms/h transdermal, Sevredol 40 mg oral 3 times daily and Ibuprofen 800 mg oral 3 times daily. Due to the risk of spinal instability and persisting pain a thoracic spondylodesis from Th 4-L2 was performed. Parallel to arrival in the PACU the patient developed extremely intensive pain. Pain control was achieved by fractional injection of overall 660 mg morphine in the first 120 min. After interviewing the patient, opioid consumption surprisingly turned out to be 60% higher than presumed. Pain therapy was continued by infusion and PCA with morphine in a daily intravenous dosage of 600-800 mg. Consecutively the pain therapy was switched to oral morphine and co-analgesics and the patient was discharged home 14 days postoperatively. ⋯ Some patients with chronic cancer pain are used to increased opioid dosages prior to planned surgery. In the perioperative setting these dosages have to be continued and adapted to current requirements, otherwise analgesic undersupply occurs. In our case report we describe a serious sequence of postoperative analgesic undersupply in an opioid consuming patient. The main principles of post-operative dosing and logistic pitfalls are illustrated.