Analgesia in the intensive care unit

Abstract

Background. Sedation is a technique of using drugs to put a patient in a condition in which he can tolerate unpleasant procedures, while maintaining cardiorespiratory function. The main problems associated with analgesia and sedation (AS) are associated with the development of hypoxia, vomiting and aspiration, hypotension and hemodynamic instability, apnea.
 Objective. To describe the features of the modern AS.
 Materials and methods. Analysis of literature data on this issue.
 Results and discussion. AS can be performed with the help of different drugs. Benzodiazepines (preferably midazolam) and/or propofol in combination with low doses of opioids should be used in patients with concomitant cardiac abnormalities. The use of propofol in this category of patients is carried out by fractional administration (on average, 50 mg) with an interval of 30-40 seconds until an adequate sedative effect is achieved. Dexmedetomidine has been suggested as an adjuvant. It should be kept in mind that benzodiazepines are not suitable for creating a long-lasting sedative effect, and can cause paradoxical agitation in the elderly. Features of sedation in patients at risk of obstructive sleep apnea syndrome are represented with the use of a minimum dose of hypnotics without the use of opioids. Dexmedetomidine is considered as an alternative. It is advisable to use continuous positive airways pressure by inhalation of oxygen through the nasal cannula. Patients with morbid obesity should avoid lying on their back. For the effective control of airway patency, it is advisable to use endotracheal intubation. It is recommended to avoid long-acting drugs and drugs that cause respiratory depression. The use of propofol in this group is often associated with respiratory complications, so the use of remifentanil and dexmedetomidine is recommended as an alternative. For patients with chronic renal failure, midazolam and/or fentanyl should be preferred, however, the cardiovascular and pulmonary side effects of any of these drugs are exacerbated when they are used concomitantly. In patients with hepatic dysfunction, midazolam may exacerbate symptoms, so propofol should be preferred. If the latter is used, the doctor should be near the patient throughout the procedure and monitor him exclusively. As for dexmedetomidine, this drug selectively binds and activates presynaptic α2-adrenoreceptors, inhibiting the release of norepinephrine. As a result, postsynaptic activation of adrenoceptors is inhibited, sympathetic activity is suppressed, leading to analgesia, sedation and decrease of anxiety. Under conditions of mild or moderate sedation caused by dexmedetomidine, patients respond to verbal stimulation and are able to communicate and cooperate with medical staff, and after awakening show high results in tests of central nervous system activity. Dexmedetomidine is less likely to cause postoperative delirium than midazolam (54 % vs. 76.6 %) and does not adversely affect sleep quality, unlike propofol. Dexmedetomidine can be used together with paracetamol. Intravenous paracetamol significantly reduces postoperative pain and the need for opioids.
 Conclusions. 1. AS can be performed with the use of benzodiazepines, propofol, dexmedetomidine. 2. Benzodiazepines are not suitable for creating a long-lasting sedative effect, and can cause paradoxical agitation in the elderly. 3. Patients with different comorbid conditions are characterized by different features of required AS. 4. Dexmedetomidine gives the patient the opportunity to communicate and cooperate with medical staff, rarely causes postoperative delirium and does not adversely affect the sleep quality. 5. Intravenous paracetamol significantly reduces postoperative pain and the need for opioids.