The Key Importance of Continuous Neurological Assessment with Validated Tools

International guidelines clearly recommend systematic assessment of pain, agita- tion/sedation, and delirium in all ICU patients, with validated tools [4-6]. They provide repeatable and comparable measurements, able to adequately titrate the

Fig. 18.1 The target level of sedation is different from the first period, devoted to clinical stabilization and protective ventilation, to the second one, when patients need to receive lighter sedation, intended to join and maintain a calm, conscious, and cooperative neurological state

analgesic, sedative, and antipsychotic therapy. The goal is to control the stress response and the neurological symptoms together keeping ARDS patients awake, cooperative, and well adapted to the necessary invasive procedures as soon as possible [28]. An excessive use of neuroactive drugs [26] correlates with longer mechanical ventilation and ICU stay, as well as with an increased risk of serious neurological consequences in both the short- and long-term [10, 29].

Among the validated tools, the scales with the highest psychometric properties [30] are the Verbal Numeric Rating (VNR), the Behavioral Pain Scale (BPS) [31], or the Critical-Care Pain Observation Tool (CPOT) [32] for the pain assessment, the Richmond Agitation-Sedation Scale (RASS) [33] and the Sedation-Agitation Scale (SAS) [34] for the agitation/sedation assessment, and the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) [35] and the Intensive Care Delirium Screening Checklist (ICDSC) [36] for the delirium assessment.

Pain assessment has become culturally essential for intensivists, both nurses and physicians. Proper identification of pain symptoms in critically ill patients represents a challenge because of complexity in communication with patients needing endotracheal respiratory prostheses, because of altered state of consciousness or because of neuroactive drugs use. To address these issues, specific behavioral scales were designed and validated both in unconscious/sedated [37] and in conscious/awake patients [38] and established as a valid, reliable, and simple tool to be used in clinical practice.

Regarding sedative drugs, their under- or overuse may compromise clinical stability. Life-threatening side effects of untreated agitation and stress response are evident: self-removal of life-sustaining devices, tachypnea, tachycardia, hypertension, sustained hypoxemia, and hypercarbia due to uncoordinated mechanical ventilation [6]. At the same time, deeper-than-necessary sedation increases the length of ICU stay [5], the duration of mechanical ventilation [21], the sepsis severity [8], and the onset of new neurological failures both during hospitalization like delirium and after discharge [29] like the development of psychological reactions of traumatic nature (posttraumatic stress disorder, PTSD). In order to obtain the best sedative titration, the use of validated tools is mandatory. For example, the RASS describes ten levels of sedation/agitation through observation and verbal and physical stimulation. Scores range from -5 (unconscious, unresponsive to voice and physical stimuli) to + 4 (overtly combative, violent, immediate danger to staff), adequately describing the possible neurological condition needing an immediate intervention.

While regarding pain and agitation evaluation encouraging results are present in literature [39], delirium recognition [40] and assessment is more challenging, since its success is linked to an effective and lasting staff training [41]. Delirium has a very high prevalence in critically ill patients [42], with a direct relationship between increased morbidity and mortality and the duration (in days) of delirium [43, 44]. The presence and duration of delirium also correlates with a significant deterioration in the quality of life after ICU discharge [45]. Large literature recommends the use of validated tools [46], like the Confusion Assessment Method for the ICU (CAM-ICU) and the Intensive Care Delirium Screening Checklist (ICDSC). The CAM-ICU has excellent sensitivity and specificity and is based on only four items (acute modification of consciousness, inattention, disorganized thinking, altered level of consciousness). This allows a shorter training to teach ICU staff members a validated way to evaluate delirium.

All these measurements have to be reported in the clinical chart at least once per shift, together with an evaluation of adequacy of sedative treatment. The neurological monitoring plays a key role in ARDS patients, and it is quick to perform. A complete example of evaluations recommended by international guidelines is reported in Fig. 18.2. Physicians have to state the desired sedation target for that specific patient at that specific moment of clinical course; nurses, on their part, report the actual neurological state, describing pain, anxiety, agitation, sleep, need for physical restraints, and delirium, together with a comprehensive evaluation of sedative therapy, in order to get the most adequate treatment titration.