A multidimensional approach to pain assessment in critically ill infants during a painful procedure

Abstract

Objectives: Inferring the pain level of a critically ill infant is complex. The ability to accurately extract the appropriate pain cues from observations is often jeopardized when heavy sedation and muscular blocking agents are administered. Near-infrared spectroscopy is a noninvasive method that may provide the bridge between behavioral observational indicators and cortical pain processing. We aimed to describe regional cerebral and systemic hemodynamic changes, as well as behavioral reactions in critically ill infants with congenital heart defects during chest-drain removal after cardiac surgery.

Methods: Our sample included 20 critically ill infants with congenital heart defects, less than 12 months of age, admitted to the cardiac intensive care unit after surgery.

Results: Cerebral deoxygenated hemoglobin concentrations significantly differed across the epochs (i.e., baseline, tactile stimulus, noxious stimulus) (P=0.01). Physiological systemic responses and Face Leg Activity Cry Consolability (FLACC) pain scores differed significantly across the events (P<0.01). The 3 outcome measures were not found to be associated with each other. Mean FLACC pain scores during the painful procedure was 7/10 despite administration of morphine. Midazolam administration accounted for 36% of the variance in pain scores.

Discussion: We demonstrated with a multidimensional pain assessment approach that significant cerebral, physiological, and behavioral activity was present in response to a noxious procedure in critically ill infants despite the administration of analgesic treatment. Considering that the sedating agent significantly dampened pain behaviors, assessment of cerebral hemodynamic in the context of pain seems to be an important addition.

Figure 1

Changes in right hemisphere [HbH] values in all subjects (n = 19). The figure shows significant [HbH] increases from baseline (T₀) to noxious stimulation (T₂) *p < 0.05. Vertical bars denote the standard deviations and the middle points denote the mean values. T₀: baseline; T₁: tactile stimulation; T₂: noxious stimulation.

Figure 2

Mean FLACC pain scores for baseline (T₀), tactile (T₁), and noxious (T₂) events between males (n = 12) and females (n = 8). The figure shows significant differences in overall FLACC scores across the three events (p < 0.001) and between males and females (p < 0.01).