[Cholinesterase inhibitors. Importance in anaesthesia, intensive care medicine, emergency medicine and pain therapy]

[Complications and emergencies in the recovery room]

The recovery room as a central monitoring unit plays a crucial role in the perioperative care of patients. Here, the patient is monitored until the subsequent transfer to a further care ward; however, due to the previous anesthesia and surgery the recovery room also provides a high risk for (the development of) complications. The present article provides an overview of the most frequent complications to be expected in the recovery room (in adults), the diagnostics and the acute treatment.

[Delirium in the intensive care unit]

In recent years delirium in the intensive care unit (ICU) has internationally become a matter of rising concern for intensive care physicians. Due to the design of highly sophisticated ventilators the practice of deep sedation is nowadays mostly obsolete. To assess a ventilated ICU patient for delirium easy to handle bedside tests have been developed which permit a psychiatric scoring. The significance of ICU delirium is equivalent to organ failure and has been proven to be an independent prognostic factor for mortality and length of ICU and hospital stay. The pathophysiology and risk factors of ICU delirium are still insufficiently understood in detail. A certain constellation of pre-existing patient-related conditions, the current diagnosis and surgical procedure and administered medication entail a higher risk for the occurrence of ICU delirium. A favored hypothesis is that an imbalance of the neurotransmitters acetylcholine and dopamine serotonin results in an unpredictable neurotransmission. Currently, the administration of neuroleptics, enforced physiotherapy, re-orientation measures and appropriate pain treatment are the basis of the therapeutic approach.

Histopathology and cholinergic assessment of Pterocarya fraxinifolia on chicken embryo

There are no reports of toxicological studies of Pterocarya fraxinifolia. The leaves are used for fishing, which also an anesthetic agent. Currently, many drugs utilized in anesthesia practice are modified cholinergic transmission and acetylcholine esterase inhibitors; these are parts of anaesthetic pharmacy. Therefore, cholinergic assessment was surveyed in chicken embryo, which Pterocarya fraxinifolia extractes were injected in 0.1, 1 and 10 mg concentration at day 4 of incubation. Serum and brain cholinesterase were analyzed on day 20 of incubation. The signs were not due to the changes of cholinesterase activity. In histopathology examination, massive necrosis was observed in the spinal cord. Other tissues such as heart, kidneys, skeletal bones and muscles, trachea and lungs, digestive system and endocrine glands were completely developed. This data suggests that the spinal cord is a target organ of the bioactive component of this plant.

Pathoetiological model of delirium: a comprehensive understanding of the neurobiology of delirium and an evidence-based approach to prevention and treatment

Delirium is the most common complication found in the general hospital setting. Yet, we know relatively little about its actual pathophysiology. This article contains a summary of what we know to date and how different proposed intrinsic and external factors may work together or by themselves to elicit the cascade of neurochemical events that leads to the development delirium. Given how devastating delirium can be, it is imperative that we better understand the causes and underlying pathophysiology. Elaborating a pathoetiology-based cohesive model to better grasp the basic mechanisms that mediate this syndrome will serve clinicians well in aspiring to find ways to correct these cascades, instituting rational treatment modalities, and developing effective preventive techniques.

Neuromuskuläre Blockade

Currently, the main aims of using neuromuscular blocking agents during general anaesthesia are the improvement of surgical and intubation conditions. Neuromuscular blocking agents themselves are neither analgesic nor anaesthetic. All agents interact with the acetylcholinergic receptor at the neuromuscular junction and induce a blockade either through a continuous activation imitating the effect of acetylcholine or through a competitive antagonism against acetylcholine. Succinylcholine is the only depolarizing muscle relaxant that is in clinical use. Non-depolarizing neuromuscular blockers may be grouped by their chemical structure into benzylisoquinolines or aminosteroids, and cover the complete range from short and intermediate, to long acting agents. Possible adverse drug reactions to the single agents are also related to their mechanism of action. Moreover, pharmacokinetic properties and effects such as histamine liberation could play an important role when choosing a myorelaxant. The depth of a neuromuscular block and recovery from paralysis can be monitored using qualitative and quantitative techniques. Therefore, the monitoring of neuromuscular recovery plays an important role in the prevention of postoperative complications due to residual paralysis. In case of residual paralysis, cholinesterase inhibitors are suitable for reversal.

Neuromuskuläre Restblockaden

Even after administration in routine clinical dosages, muscle relaxants can lead to long-lasting residual blockades which increase the risk of severe postoperative pulmonary complications. Even without the additional effects from analgetics, sedatives or anaesthetics, a partial neuromuscular blockade, which cannot reliably be avoided either by the anaesthetist alone or by the additional use of nerve stimulators (train-of-four [TOF] ratio 0.5-0.9), can cause reductions in the vital capacity and the hypoxic breathing response, as well as obstruction of the upper airway and disruption of pharangeal function. The extent of neuromuscular recovery after an operation depends on the muscle relaxant used, the duration of administration, the anaesthetic technique and possible accompanying illnesses of the patient. It must basically be assumed that residual neuromuscular blockades are more frequent after administration of slow acting muscle relaxants such as pancuronium, than after the use of medium or rapid acting substances. If the course of a neuromuscular blockade is continually monitored during the whole anaesthetic procedure using the TOF ratio and not only occasionally at the end, a TOF ratio of 1 measured with an acceleromyograph (e.g. TOF-watch) promises an adequate neuromuscular recovery from the effects of muscle relaxants.