Céline Gélinas, PhD, RN
Professor and Senior Researcher
3Ingram School of Nursing, McGill University, and Centre for Nursing Research, Jewish General Hospital – CIUSSS West-Central Montréal, Montréal, QC, Canada, Quebec, Canada
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Title: The Validity of Vital Signs for Pain Assessment in Critically Ill Adults.
Introduction: Most critically ill adults experience pain during their stay in the Intensive Care Unit (ICU). Pain assessment is challenging in this population due to the inability to self-report or exhibit pain-related behaviours. In such situations, vital signs (VS) through continuous monitoring are the sole alternatives for pain assessment. The SCCM practice guidelines highlighted the lack of specificity of VS for ICU pain assessment purposes from studies published until 2015. Therefore, an updated review is timely to address the following research question: “What is the validity of VS for pain assessment in critically ill adults?”
Methods: A narrative review was conducted with a comprehensive search in four databases (Medline, Embase, CINAHL, Cochrane) from their date of inception to June 16th, 2020. The search terms were vital signs, pain assessment, and ICU. The Scale for the Assessment of Narrative Review Articles (SANRA) was followed.
Results: Out of 1215 results, 22 studies from 12 countries were included. Heart rate (n=22 studies), blood pressure (n=20), and respiratory rate (n=12) were most used for ICU pain assessment. Assessments were performed at rest pre-procedures, during nociceptive and non-nociceptive procedures, and 15-20 minutes post-procedures. VS increased significantly during nociceptive procedures (e.g., endotracheal suctioning, turning) compared with rest and non-nociceptive procedures (e.g., blood pressure cuff inflation, eye care). This increase was up to 14% for heart rate (range:2-15 bpm), 20% for systolic and diastolic blood pressure (3-23 mmHg), 13% for mean blood pressure (2-10 mmHg), and 29% for respiratory rate (2-6 brpm). ICU experts deem a change in values by >20% as clinically significant. Thus, only respiratory rate showed clinically significant increases during nociceptive procedures. Correlations of VS with self-reported pain (the gold standard measure) and behavioural pain scores were absent or weak (r< 0.30) suggesting their lack of validity for ICU pain assessment.
Conclusions: This updated review dissuades the use of VS for ICU pain assessment. Consistent with SCCM practice guidelines, VS should only be used as cues for initiating further pain assessment with validated tools. New physiological measurement technologies should be explored.