Analgesia and sedation in patients with ARDS

Abstract

Acute Respiratory Distress Syndrome (ARDS) is one of the most demanding conditions in an Intensive Care Unit (ICU). Management of analgesia and sedation in ARDS is particularly challenging. An expert panel was convened to produce a "state-of-the-art" article to support clinicians in the optimal management of analgesia/sedation in mechanically ventilated adults with ARDS, including those with COVID-19. Current ICU analgesia/sedation guidelines promote analgesia first and minimization of sedation, wakefulness, delirium prevention and early rehabilitation to facilitate ventilator and ICU liberation. However, these strategies cannot always be applied to patients with ARDS who sometimes require deep sedation and/or paralysis. Patients with severe ARDS may be under-represented in analgesia/sedation studies and currently recommended strategies may not be feasible. With lightened sedation, distress-related symptoms (e.g., pain and discomfort, anxiety, dyspnea) and patient-ventilator asynchrony should be systematically assessed and managed through interprofessional collaboration, prioritizing analgesia and anxiolysis. Adaptation of ventilator settings (e.g., use of a pressure-set mode, spontaneous breathing, sensitive inspiratory trigger) should be systematically considered before additional medications are administered. Managing the mechanical ventilator is of paramount importance to avoid the unnecessary use of deep sedation and/or paralysis. Therefore, applying an "ABCDEF-R" bundle (R = Respiratory-drive-control) may be beneficial in ARDS patients. Further studies are needed, especially regarding the use and long-term effects of fast-offset drugs (e.g., remifentanil, volatile anesthetics) and the electrophysiological assessment of analgesia/sedation (e.g., electroencephalogram devices, heart-rate variability, and video pupillometry). This review is particularly relevant during the COVID-19 pandemic given drug shortages and limited ICU-bed capacity.

Keywords: Acute respiratory distress syndrome; Analgesia; COVID-19; Intensive care unit; Mechanical ventilation; Rehabilitation; Sedation.

Fig. 1

Analgesia and sedation without NMBA for protective lung ventilation strategy. ^A Analgesia-first/minimal sedation is the default option. ^B Clinicians choose the desirable sedation level based on patients' symptoms. ^C Propofol remains the first line for titrated sedation. Adding dexmedetomidine could be considered to reduce emergent delirium and reduce propofol cumulative dose. In selected cases (patients who are refractory to propofol ± dexmedetomidine sedation, or to decrease the dose of sedatives), consider using intermittent benzodiazepines, anti-psychotic agents, or a volatile anesthetic. RASS: Richmond Agitation Sedation Scale (− 5 is unresponsive to physical stimulation, − 4 open eyes or move to physical stimulation, − 3 open eyes or move to voice, − 2 make eye contact < 10 s, − 1 make eye contact > 10 s, 0 alert and calm, + 1 restless, + 2 agitated, + 3 very agitated, + 4 combative) score [21]. SAS: Sedation Agitation Scale (1 unarousable, 2 very sedated, 3 sedated, 4 calm and cooperative and awakens easily, 5 agitated, 6 very agitated, and 7 dangerous agitation) [20]. BPS: Behavioral Pain Scale [2, 16]. CPOT: Critical-Care Pain Observation Tool [2, 16]. CAM-ICU: Confusion Assessment Method – Intensive Care Unit [2]. ICDSC: Intensive Care Delirium Screening Checklist [2]

Fig. 2

Proposition of an algorithm for troubleshooting mechanical ventilator adjustments, adapted from [6, 25]. ^APatients related factors include stress related symptoms (e.g. pain, discomfort, anxiety, dyspnea) and physiological factors (e.g. hyperthermia, acidosis, hypercapnia). ABG arterial blood gas, ACV assist-control volume, APRV Airway Pressure Release Ventilation, ARDS acute respiratory distress syndrome, PEEP positive end-expiratory pressure, PSV pressure-support ventilation, NMBA neuromuscular blocking agent, RR respiratory rate

Fig. 3

Updated ABCDEF-R bundle for mechanically ventilated patients, including patients with ARDS, adapted from [–45]