The necessity of optimal analgesia for intensive care patients

Intensive care medical therapy measures are associated with considerable pain. Adequate pain control (analgesia) is an essential component of any intensive medical therapy.

Inadequate analgesia can be hazardous for patients due to agitation and stress responses, for example. Excessive analgesic therapy can also have harmful consequences such as an increased likelihood of developing, and developing more severe, concentration-dependent adverse reactions to analgesics and prolongation of the ventilation time. Both overdosing and underdosing of analgesics can increase the mortality and morbidity of patients and lead to rising therapy costs.

For these reasons, the German Society of Anaesthesiology and Intensive Care Medicine stress in their guideline on analgesic sedation the absolute necessity of ensuring optimal analgesia in addition to sedation.

Issues with the dosage of analgesics for non-communicative intensive care patients

The difficulty of determining the dosage of analgesics for non-communicative patients, such as sedated patients in intensive care units, is also emphasised in this guideline. The conventional dosage based on clinical parameters such as movement responses, facial expressions or changes in heart rate or blood pressure is known to be inexact: the strong dependence of these signs on non-painful factors results in a low pain specificity, meaning that if there are changes in the clinical parameters it cannot be reliably concluded that the patient has actually felt pain. Along with this lack of specificity, it is also known that the conventional clinical parameters also have a low pain sensitivity: patients can therefore also be suffering severe pain without this being reflected in the clinical parameters.

Experimental instrument-based techniques to measure analgesia in non-communicative patients, for example, techniques based on the interpretation of an electroencephalogram or changes in the activity of the autonomic nervous system (e.g., electrical skin resistance or heart rate variability) have not been able to provide satisfactory results in clinical application due to the low pain specificity of the techniques.

Benefits of automatic pain reflex measurement

The novel technique of automatic pain reflex measurement provides not only specific and sensitive information about the extent of pain control in such non-communicative patients but as a continuous technique, it enables monitoring of the course of the analgesia over a longer period in addition to determining the extent of the analgesia at a particular time point.