Effects of acute postoperative pain on catecholamine plasma levels, hemodynamic parameters, and cardiac autonomic control

Abstract

Postoperative pain is often stated to be a significant contributor to a sympathetic stress response after surgery. However, hardly any evidence has been published to support this assumption. Hence it was the aim of this trial to investigate the relationship between postoperative pain and hemodynamic, endocrine, and autonomic parameters. A total of 85 postoperative patients in the recovery room were repeatedly asked to rate their pain on a numeric rating scale (NRS). Concurrently, the parameters of heart rate variability (HRV) were analysed, and mean arterial pressure (MAP), heart rate (HR) and respiration rate (RR) were recorded. Pain was categorized into no, mild, moderate, and severe. Blood samples were taken for epinephrine (EPI) and norepinephrine (NE) plasma level assessment at the time of recovery room admission and discharge, and each time pain was found decreased in categorized severity. A total of 239 pain readings were obtained. None of the investigated parameters correlated with NRS scores. NE was higher at NRS 5 to 10 vs. NRS 0 to 4 (mean [SEM]: 1009 [73] pg/mL vs. 872 [65] pg/mL; P<0.01). This was also found for MAP, but not for EPI or the parameters of HRV, HR, and RR. In contrast to common belief, the severity of postoperative pain does not appear to be associated with the degree of sympathetic stress response after surgery, and other factors such as surgical trauma may be more important. Importantly, the absence of signs of sympathetic stimulation cannot be seen as a guarantee for the absence of significant pain.

Vital Signs Are Not Associated with Self-Reported Acute Pain Intensity in the Emergency Department

“…[22][23][24][25][26][27][28][29][30] Pain intensity is subjective, and with conflicting results, researchers have tried to identify unbiased parameters (including vital signs) to validate pain intensity. HR (or HR variability), more than blood pressure, has been associated with pain intensity, [22][23][24]27,[31][32][33][34] but mostly in males. 29,30 Some studies do not support this association.…”

“…24,26 However, as was the case for HR, other investigations reported an absence of relationship. 28,33,35,39 Most studies have failed to show an association between pain and respiratory rate. 22,24,26,28,31,33,37,39 Transcutaneous oxygen, skin conductance, and the analgesia/nociception index (calculated from HR variability) have been assessed in patients experiencing pain with inconsistent conclusions.…”

“…28,33,35,39 Most studies have failed to show an association between pain and respiratory rate. 22,24,26,28,31,33,37,39 Transcutaneous oxygen, skin conductance, and the analgesia/nociception index (calculated from HR variability) have been assessed in patients experiencing pain with inconsistent conclusions. 23,27,31,32,34,38,[40][41][42] Patients with severe pain who show no hypertension or tachycardia to substantiate their pain intensity might not receive the aggressive pain treatment they warrant.…”

Cognitive self-regulation influences pain-related physiology

“…It has been a long-standing challenge for clinicians and researchers to find physiological markers for pain (38). The predictive modeling approach used here represents a potential avenue through which quantitative biological measures related to pain can be developed and tested across studies.…”

Diagnosis of Pain in Small Companion Animals

“…It can produce changes in the heart and respiratory rate, blood pressure, capillary perfusion, ventilation, gastrointestinal motility, urinary functions, muscle contractility and nervous activity, as well as changes in glucose content, protein and lipid metabolism, water-electrolyte balance, blood concentrations of cortisol, β-endorphin, catecholamines, glucagon, ADH, insulin, etc. (Grant, 2006a;Ledowski et al, 2012).…”