patients; significant correlation with applied dosages of analgesics and sedatives [95].

COMFORT-scale: Application in pediatric intensive care units; consists of 8 easily determinable parameters to evaluate the level of sedation during the daily nursing measures [96].

Analgesia monitoring (see Fig. 2)

After evaluation of the level of sedation and analgesia, an individual aim for sedation and analgesia should be determined according to these scoring systems. The achievement of this aim should be verified on a regular basis (at least every 8 hours). A reevaluation and re-defining of the level of sedation and analgesia should also be carried out regularly.

Analgosedation (Table 3)

As there is a vast number of available preparations for an analgosedation, it is necessary to develop standard operating procedures [97]. It must not necessarily be decisive which concept is applied but that the concept is consequently and correctly applied.

Apart from an adequate sedation and analgesia, an adequate anxiolysis and vegetative protection are desirable. Modern concepts for analgosedation are based on a controlled sedation of the patient’s state of awareness and an effective elimination of pain perception. They are not meant as a prolongation of a general anesthesia.

In severely burned patients a deeper sedation is often necessary. This holds true for patients with pronounced edema in the face and the upper respiratory tract. In such patients an accidental self-extubation can be a vital danger. A deeper analgosedation can also be necessary for a particular positioning of the patient due to the localization of the burn wound and to protect fresh skin grafts that are prone to shearing forces. However, this increases the risk for ventilator-induced pneumonia. In such cases the situation must be evaluated by the health care personnel depending on the patient’s general condition and the surgical and pulmonary situation [98].

Sedation

Today there are various methods for the sedation of intensive care patients. The medication should not be ended abruptly after long-time sedation but slowly. Sedation and weaning protocols make this process easier and respiration time is reduced [99]. Sedatives must not be administered as a replacement for analgesics.

Propofol

Propofol is approved for sedation in intensive care for a maximum of 7 days. It has sedative-hypnotic, but no analgesic effects. Due to its short and con- text-sensitive half-life and the production of inac-

Table 3. Sedoanalgesia in the intensive care unit

*Calculation of the pumpfrequency (ml/h)

depending on breath volume per minute by nomogram

tive metabolites, the preparation is well controllable. Problems during application might occur through falling blood pressure and additional fat supply (1 ml = 0.1 g fat). A dosage limitation ( > 4 mg/ kg/h) is required to minimize the risk of a propofol- infusion-syndrome. This is characterized by cardiac arrythmia, heart failure, rhabdomyolysis, severe metabolic acidosis and acute renal failure. Regular checks in the laboratory (in particular ph-value and lactate) facilitate an early detection of this syndrome. Propofol is approved for the sedation of children older than 16 years.

Fröhlich et al. evaluated in a randomized pla- cebo-controlled study the effect of propofol to pain sensation with temperature stimulus (45°C, 47 °C and 49°C). Propofol was administered as targetcontrolled infusion in 2 different concentrations (0.5 μ/ml and 1.0 μ/ml) to 18 test subjects. Pain intensity was measured by the visual analogous scale. Surprisingly, the authors could prove that propofol in mild and moderate doses increased the pain intensity and the patients’ discontentment. Thus a sedation should always be combined with sufficient analgesia [100].

Benzodiazepine

Benzodiazepine centrally enforces the inhibiting effect of -aminobutyric acid and has anxioloytic, sed- ative-hypnotic, centrally relaxing and anticonvulsant effects. It is administered during long-term sedation ( > 3 days). Compared to other benzodiazepines, midazolam has a shorter context-sensitive half-life and thus is very well suited. Another benefit is an anterograde amnesia caused by benzodiazepine. Liver and renal dysfunctions cause an extensively longer action time.

Clonidine

Clonidin is a presynaptic 2-adrenoceptorantagonist with antihypertensive, analgesic, sedative and anxiolytic activity. It is administered as basic sedation (particularly in hypertensive patients), as prohylactic and in the therapy of withdrawal symptoms after long-time analgosedation and in preexisting alcoholism. Furthermore, clonidine causes a dosage reduction of sedatives and opioids and thus reduces

the side effects induced by these preparations. However, complications as for example bradycardic arrhythmia, dropping blood pressure and inhibition of the gastro-intestinal motility have to be considered. After long-time application, the administration of clonidine must be stopped slowly and gradually to avoid a rapid increase of the blood pressure.

Ketamine

Ketamine is a non-competitive NMDA-receptor-an- tagonist with dosage dependent activity. A higher dosage causes somnolence up to dissociate anesthesia (dissociation from the environment without sleeping). Due to the psychomimetic side-effects, ketamine should be administered in combination with propofol and benzodiazepine. Ketamine has proven beneficial in patients with bronchospasm or hypotensive circulation without cardiogenic reasons. However, ketamine stimulates the cardiovascular system by sensitizing the heart to catecholamines. A potential increase of the arterial blood pressure, tachycardia and increase of the myocardiac oxygen consumption have to be considered.

In subanesthetic dosages, ketamine acts exclusively as analgesic. Numerous studies have shown that ketamine can suppress effectively an opioid tolerance and an opioid-induced hyperalgesia [35, 38, 101]. The opioid-reducing property of ketamine could also be proven in intensive care patients [102].

Volatile anesthetics

A long-term sedation by intravenous preparations is associated with respiratory depression, enteroparesis, renal and liver disorders and accumulation with retarded recovery. Volatile anesthetics can be an effective alternative. For this purpose special recirculation systems for inhalational anesthetics have been developed for the use in the intensive care unit (e. g. Anesthetic Conserving Device, suitable for isoflurane and sevoflurane). At present, however, there are no sufficient studies on the importance of volatile anesthetics in analgosedation in the intensive care unit. There are single case reports of a successful application in burn patients [103].